Whenever I am running a program on Eclipse, my tomcat is failing to start. I get a dialog box stating this message

Server Tomcat v7.0 Server at localhost failed to start.

In the console, I am getting this messages

Nov 17, 2011 11:56:04 AM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Java\jre6\bin;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;C:/Program Files/Java/jre6/bin/client;C:/Program Files/Java/jre6/bin;C:/Program Files/Java/jre6/lib/i386;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Java\jdk1.6.0_01\bin;C:\Program Files\Java\jre1.6.0_01\bin;C:\ILOG\CPLEX_Studio_Preview122\opl\bin\x86_win32;C:\ILOG\CPLEX_Studio_Preview122\opl\oplide\;C:\ILOG\CPLEX_Studio_Preview122\cplex\bin\x86_win32;C:\ILOG\CPLEX_Studio_Preview122\cpoptimizer\bin\x86_win32;;D:\JSP_Setup\eclipse-jee-helios-SR2-win32\eclipse;;.
Nov 17, 2011 11:56:04 AM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:servletConfigTest' did not find a matching property.
Nov 17, 2011 11:56:04 AM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:BeerAdvice3' did not find a matching property.
Nov 17, 2011 11:56:04 AM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:BeerAdvice1' did not find a matching property.
Nov 17, 2011 11:56:05 AM org.apache.coyote.http11.Http11Protocol init
INFO: Initializing Coyote HTTP/1.1 on http-8080
Nov 17, 2011 11:56:05 AM org.apache.coyote.ajp.AjpProtocol init
INFO: Initializing Coyote AJP/1.3 on ajp-8009
Nov 17, 2011 11:56:05 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 682 ms
Nov 17, 2011 11:56:05 AM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
Nov 17, 2011 11:56:05 AM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.2
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:415)
Caused by: java.lang.IllegalArgumentException: Invalid <url-pattern> entry_checking in servlet mapping
    at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:2823)
    at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:2799)
    at org.apache.catalina.deploy.WebXml.configureContext(WebXml.java:1278)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1255)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:878)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:313)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:89)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:4667)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:139)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:988)
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:771)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:139)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:988)
    at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:275)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:139)
    at org.apache.catalina.core.StandardService.startInternal(StandardService.java:427)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:139)
    at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:649)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:139)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:585)
    ... 6 more

I had run the code previously, but now it is giving this problems.

Also, I went through this post http://forums.opensuse.org/applications/391114-tomcat6-eclipse-not-working.html

But is not helping me.

Please help at the earliest.