I am trying to apply the ServiceKnownTypeAttribute to my WCF Service but keep getting the error below my config. Does anyone have any ideas? <object id="HHGEstimating" type="Spring.ServiceModel.ServiceExporter, Spring.Services"> <property name="TargetName" value="HHGEstimatingHelper"/> <property name="Name" value="HHGEstimating"/> <property name="Namespace" value="http://www.igcsoftware.com/HHGEstimating"/> <property name="TypeAttributes"> <list> <ref local="wcfErrorBehavior"/> <ref local="wcfSilverlightFaultBehavior"/> <object type="System.ServiceModel.ServiceKnownTypeAttribute, System.ServiceModel"> <constructor-arg name="type" value="IGCSoftware.HHG.Business.UserControl.AtlasUser, IGCSoftware.HHG.Business"/> </object> </list> </property> Error thrown by a dependency of object 'HHGEstimating' defined in 'assembly [IGCSoftware.HHG.WebService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], resource [IGCSoftware.HHG.WebService.Resources.Spring.objects.xml] line 46' : '1' constructor arguments specified but no matching constructor found in object 'System.ServiceModel.ServiceKnownTypeAttribute#25A5628' (hint: specify argument indexes, names, or types to avoid ambiguities). while resolving 'TypeAttributes[2]' to 'System.ServiceModel.ServiceKnownTypeAttribute#25A5628' defined in 'assembly [IGCSoftware.HHG.WebService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], resource [IGCSoftware.HHG.WebService.Resources.Spring.objects.xml] line 46' Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: Spring.Objects.Factory.ObjectCreationException: Error thrown by a dependency of object 'HHGEstimating' defined in 'assembly [IGCSoftware.HHG.WebService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], resource [IGCSoftware.HHG.WebService.Resources.Spring.objects.xml] line 46' : '1' constructor arguments specified but no matching constructor found in object 'System.ServiceModel.ServiceKnownTypeAttribute#25A5628' (hint: specify argument indexes, names, or types to avoid ambiguities). while resolving 'TypeAttributes[2]' to 'System.ServiceModel.ServiceKnownTypeAttribute#25A5628' defined in 'assembly [IGCSoftware.HHG.WebService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], resource [IGCSoftware.HHG.WebService.Resources.Spring.objects.xml] line 46' Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [ObjectCreationException: Error thrown by a dependency of object 'HHGEstimating' defined in 'assembly [IGCSoftware.HHG.WebService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], resource [IGCSoftware.HHG.WebService.Resources.Spring.objects.xml] line 46' : '1' constructor arguments specified but no matching constructor found in object 'System.ServiceModel.ServiceKnownTypeAttribute#25A5628' (hint: specify argument indexes, names, or types to avoid ambiguities). while resolving 'TypeAttributes[2]' to 'System.ServiceModel.ServiceKnownTypeAttribute#25A5628' defined in 'assembly [IGCSoftware.HHG.WebService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], resource [IGCSoftware.HHG.WebService.Resources.Spring.objects.xml] line 46'] Spring.Objects.Factory.Support.ObjectDefinitionValueResolver.ResolveInnerObjectDefinition(String name, String innerObjectName, String argumentName, IObjectDefinition definition, Boolean singletonOwner) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\ObjectDefinitionValueResolver.cs:300 Spring.Objects.Factory.Support.ObjectDefinitionValueResolver.ResolvePropertyValue(String name, IObjectDefinition definition, String argumentName, Object argumentValue) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\ObjectDefinitionValueResolver.cs:150 Spring.Objects.Factory.Support.ObjectDefinitionValueResolver.ResolveValueIfNecessary(String name, IObjectDefinition definition, String argumentName, Object argumentValue) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\ObjectDefinitionValueResolver.cs:112 Spring.Objects.Factory.Config.ManagedList.Resolve(String objectName, IObjectDefinition definition, String propertyName, ManagedCollectionElementResolver resolver) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Config\ManagedList.cs:126 Spring.Objects.Factory.Support.ObjectDefinitionValueResolver.ResolvePropertyValue(String name, IObjectDefinition definition, String argumentName, Object argumentValue) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\ObjectDefinitionValueResolver.cs:201 Spring.Objects.Factory.Support.ObjectDefinitionValueResolver.ResolveValueIfNecessary(String name, IObjectDefinition definition, String argumentName, Object argumentValue) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\ObjectDefinitionValueResolver.cs:112 Spring.Objects.Factory.Support.AbstractAutowireCapableObjectFactory.ApplyPropertyValues(String name, RootObjectDefinition definition, IObjectWrapper wrapper, IPropertyValues properties) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\AbstractAutowireCapableObjectFactory.cs:373 Spring.Objects.Factory.Support.AbstractAutowireCapableObjectFactory.PopulateObject(String name, RootObjectDefinition definition, IObjectWrapper wrapper) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\AbstractAutowireCapableObjectFactory.cs:563 Spring.Objects.Factory.Support.AbstractAutowireCapableObjectFactory.ConfigureObject(String name, RootObjectDefinition definition, IObjectWrapper wrapper) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\AbstractAutowireCapableObjectFactory.cs:1844 Spring.Objects.Factory.Support.AbstractAutowireCapableObjectFactory.InstantiateObject(String name, RootObjectDefinition definition, Object[] arguments, Boolean allowEagerCaching, Boolean suppressConfigure) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\AbstractAutowireCapableObjectFactory.cs:918 Spring.Objects.Factory.Support.AbstractObjectFactory.CreateAndCacheSingletonInstance(String objectName, RootObjectDefinition objectDefinition, Object[] arguments) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\AbstractObjectFactory.cs:2120 Spring.Objects.Factory.Support.AbstractObjectFactory.GetObjectInternal(String name, Type requiredType, Object[] arguments, Boolean suppressConfigure) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\AbstractObjectFactory.cs:2046 Spring.Objects.Factory.Support.DefaultListableObjectFactory.PreInstantiateSingletons() in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Objects\Factory\Support\DefaultListableObjectFactory.cs:505 Spring.Context.Support.AbstractApplicationContext.Refresh() in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Context\Support\AbstractApplicationContext.cs:911 _dynamic_Spring.Context.Support.XmlApplicationContext..ctor(Object[] ) +197 Spring.Reflection.Dynamic.SafeConstructor.Invoke(Object[] arguments) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Reflection\Dynamic\DynamicConstructor.cs:116 Spring.Context.Support.RootContextInstantiator.InvokeContextConstructor(ConstructorInfo ctor) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Context\Support\ContextHandler.cs:550 Spring.Context.Support.ContextInstantiator.InstantiateContext() in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Context\Support\ContextHandler.cs:494 Spring.Context.Support.ContextHandler.InstantiateContext(IApplicationContext parentContext, Object configContext, String contextName, Type contextType, Boolean caseSensitive, String[] resources) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Context\Support\ContextHandler.cs:330 Spring.Context.Support.ContextHandler.Create(Object parent, Object configContext, XmlNode section) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Context\Support\ContextHandler.cs:280 [ConfigurationErrorsException: Error creating context 'spring.root': Error thrown by a dependency of object 'HHGEstimating' defined in 'assembly [IGCSoftware.HHG.WebService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], resource [IGCSoftware.HHG.WebService.Resources.Spring.objects.xml] line 46' : '1' constructor arguments specified but no matching constructor found in object 'System.ServiceModel.ServiceKnownTypeAttribute#25A5628' (hint: specify argument indexes, names, or types to avoid ambiguities). while resolving 'TypeAttributes[2]' to 'System.ServiceModel.ServiceKnownTypeAttribute#25A5628' defined in 'assembly [IGCSoftware.HHG.WebService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], resource [IGCSoftware.HHG.WebService.Resources.Spring.objects.xml] line 46'] System.Configuration.BaseConfigurationRecord.EvaluateOne(String[] keys, SectionInput input, Boolean isTrusted, FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentResult) +202 System.Configuration.BaseConfigurationRecord.Evaluate(FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentResult, Boolean getLkg, Boolean getRuntimeObject, Object& result, Object& resultRuntimeObject) +1061 System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject) +1431 System.Configuration.BaseConfigurationRecord.GetSection(String configKey, Boolean getLkg, Boolean checkPermission) +56 System.Configuration.BaseConfigurationRecord.GetSection(String configKey) +8 System.Web.Configuration.HttpConfigurationSystem.GetApplicationSection(String sectionName) +45 System.Web.Configuration.HttpConfigurationSystem.GetSection(String sectionName) +49 System.Web.Configuration.HttpConfigurationSystem.System.Configuration.Internal.IInternalConfigSystem.GetSection(String configKey) +6 System.Configuration.ConfigurationManager.GetSection(String sectionName) +78 Spring.Util.ConfigurationUtils.GetSection(String sectionName) in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Util\ConfigurationUtils.cs:69 Spring.Context.Support.ContextRegistry.InitializeContextIfNeeded() in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Context\Support\ContextRegistry.cs:340 Spring.Context.Support.ContextRegistry.GetContext() in l:\projects\spring-net\trunk\src\Spring\Spring.Core\Context\Support\ContextRegistry.cs:206 Spring.ServiceModel.Activation.ServiceHostFactory.CreateServiceHost(String reference, Uri[] baseAddresses) in l:\projects\spring-net\trunk\src\Spring\Spring.Services\ServiceModel\Activation\ServiceHostFactory.cs:66 System.ServiceModel.HostingManager.CreateService(String normalizedVirtualPath) +11687036 System.ServiceModel.HostingManager.ActivateService(String normalizedVirtualPath) +42 System.ServiceModel.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath) +479 [ServiceActivationException: The service '/HHGEstimating.svc' cannot be activated due to an exception during compilation. The exception message is: Error creating context 'spring.root': Error thrown by a dependency of object 'HHGEstimating' defined in 'assembly [IGCSoftware.HHG.WebService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], resource [IGCSoftware.HHG.WebService.Resources.Spring.objects.xml] line 46' : '1' constructor arguments specified but no matching constructor found in object 'System.ServiceModel.ServiceKnownTypeAttribute#25A5628' (hint: specify argument indexes, names, or types to avoid ambiguities). while resolving 'TypeAttributes[2]' to 'System.ServiceModel.ServiceKnownTypeAttribute#25A5628' defined in 'assembly [IGCSoftware.HHG.WebService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], resource [IGCSoftware.HHG.WebService.Resources.Spring.objects.xml] line 46'.] System.ServiceModel.AsyncResult.End(IAsyncResult result) +11592858 System.ServiceModel.Activation.HostedHttpRequestAsyncResult.End(IAsyncResult result) +194 System.ServiceModel.Activation.HostedHttpRequestAsyncResult.ExecuteSynchronous(HttpApplication context, Boolean flowContext) +176 System.ServiceModel.Activation.HttpModule.ProcessRequest(Object sender, EventArgs e) +275 System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +68 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75