We have a solution with two projects, one of them is a Silverlight 3 application which is embedded on the other ASP.NET MVC project. Just recently an error started to appear which makes the build fail. Here is the output:

`------ Build started: Project: DotCoquiMap, Configuration: Debug Any CPU ------ C:\Program Files\MSBuild\Microsoft\Silverlight\v3.0\Microsoft.Ria.Client.targets : warning : Could not find necessary input file 'C:\Users\Michael\Documents\DotCoqui\trunk\DotCoquiMap\Bin\Debug\DotCoquiMap.dll'. Done building project "DotCoquiMap.csproj" -- FAILED. ------ Build started: Project: DotCoquiProject, Configuration: Debug Any CPU ------ C:\Windows\Microsoft.NET\Framework\v3.5\Csc.exe /noconfig /nowarn:1701,1702 /errorreport:prompt /warn:4 /define:DEBUG;TRACE /reference:C:\Users\Michael\Documents\DotCoqui\trunk\DotCoquiMap\Bin\Debug\DotCoquiMap.dll /reference:..\ExternalLibraries\itextsharp.dll /reference:..\ExternalLibraries\MvcMembership.dll /reference:..\ExternalLibraries\PagedList.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Configuration.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Core.dll" /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Data.DataSetExtensions.dll" /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Data.Linq.dll" /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Drawing.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.EnterpriseServices.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Web.Abstractions.dll" /reference:............\Windows\assembly\GAC_MSIL\System.Web.DataVisualization\3.5.0.0__31bf3856ad364e35\System.Web.DataVisualization.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Web.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Web.Extensions.dll" /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Web.Mobile.dll /reference:"C:\Program Files\Microsoft ASP.NET\ASP.NET MVC 1.0\Assemblies\System.Web.Mvc.dll" /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Web.Routing.dll" /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Web.Services.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Xml.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Xml.Linq.dll" /debug+ /debug:full /optimize- /out:obj\Debug\DotCoquiProject.dll /target:library Controllers\AccountController.cs Controllers\AdministrationController.cs Controllers\ApiController.cs Controllers\CampaignsCategoriesController.cs Controllers\CampaignsController.cs Controllers\CampaignsFormViewModel.cs Controllers\CampaignStatisticsController.cs Controllers\CampaignStatisticsDetailsViewModel.cs Controllers\ControllerHelpers.cs Controllers\CountriesController.cs Controllers\ErrorController.cs Controllers\HomeController.cs Controllers\MapController.cs Controllers\MediaController.cs Controllers\MediaViewModel.cs Controllers\NewsController.cs Controllers\OrganizationsController.cs Controllers\OrgCenterController.cs Controllers\UserAdministrationController.cs Default.aspx.cs Global.asax.cs Models\Campaigns.cs Models\CategoriesRuleValidation.cs Models\DotCoquiDBModel.designer.cs Models\DotCoquiRepository.cs Models\DQcodes.cs Models\FileRepository.cs Models\ISmtpClient.cs Models\JsonModels.cs Models\OrgCenter\IndexViewModel.cs Models\SmtpClientProxy.cs Models\Statistic.cs Models\User.cs Models\UserAdministration\DetailsViewModel.cs Models\UserAdministration\IndexViewModel.cs Models\UserAdministration\RoleViewModel.cs Properties\AssemblyInfo.cs error CS0006: Metadata file 'C:\Users\Michael\Documents\DotCoqui\trunk\DotCoquiMap\Bin\Debug\DotCoquiMap.dll' could not be found

Compile complete -- 1 errors, 0 warnings ========== Build: 0 succeeded or up-to-date, 2 failed, 0 skipped ==========`

And here is the errors / warnings:

Warning 2 Could not find necessary input file 'C:\Users\Michael\Documents\DotCoqui\trunk\DotCoquiMap\Bin\Debug\DotCoquiMap.dll'. DotCoquiMap

Error 1 Metadata file 'C:\Users\Michael\Documents\DotCoqui\trunk\DotCoquiMap\Bin\Debug\DotCoquiMap.dll' could not be found DotCoquiProject

The DotCoquiMap is not getting built therefore the DotCoquiProject (ASP.NET MVC) cannot find the .dll.

Now here is the really odd thing, under Windows XP the very same code compiles and runs perfectly.... under windows 7 it gives us these errors. It is the very same code, we have tested it on 3 different Win7 machines to no avail.

Help will be really really helpful. Thanks in advance.