Error fetching item: Not Found - Error code 404 with JSP

Hello,

in our TeamConcert Installation we get the following error during open
JSP Files in the Source Control View of the Web UI.
Error fetching item: Not Found - Error code 404
The error appears with new and older Files.
We also try to upload a completely new JSP File. Then the File appears and when we click on it also the error appears.
When we open the Files with the Rational Team Concert Client, there are no problems everything seems to be ok.
The error only appears in the Web Frontend.
We checked the Jazz and DB2 Log files, no exceptions or errors were thrown.

Our Installation:
AppServer: Websphere 6.1.0.21
Jazz Foundation - Jazz Team Server 1.0.0.2 iFix 3 (I20100602-1000)
Rational Team Concert 2.0.0.2 iFix 3 (I20100602-1000)

Do you have any ideas?

Update:
After some additional research we found this exception:

java.io.FileNotFoundException: JSPG0036E: Die Ressource /resource/virtualPath/com.ibm.team.scm.rest2.dto.VersionablePlusDTO/~KSKSearch/WebContent/advancedSearchResults.jsp wurde nicht gefunden.

	at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionProcessor.findWrapper(AbstractJSPExtensionProcessor.java:308)

	at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionProcessor.handleRequest(AbstractJSPExtensionProcessor.java:281)

	at com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:3444)

	at com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:267)

	at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:815)

	at com.ibm.ws.wswebcontainer.WebContainer.handleRequest(WebContainer.java:1466)

	at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:119)

	at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:458)

	at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewInformation(HttpInboundLink.java:387)

	at com.ibm.ws.http.channel.inbound.impl.HttpICLReadCallback.complete(HttpICLReadCallback.java:102)

	at com.ibm.ws.ssl.channel.impl.SSLReadServiceContext$SSLReadCompletedCallback.complete(SSLReadServiceContext.java:1818)

	at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165)

	at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217)

	at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161)

	at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:136)

	at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:195)

	at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:743)

	at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:873)

	at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1473)

With a little search on google we set the following parameter on the Websphere Server:
com.ibm.ws.webcontainer.invokefilterscompatibility=true

But this doesn't help so far.