Since Google did not return any hits for the error we had on one of our servers I add it here for future references. The error logged in SystemOut.log was
ContainerHelp E WSVR0501E: Error creating component com.ibm.ws.runtime.component.CompositionUnitMgrImpl@593e2ce7
com.ibm.ws.exception.RuntimeWarning: com.ibm.ws.exception.RuntimeError: java.lang.RuntimeException: java.lang.VerifyError: JVMVRFY024 arguments are not type compatible; class="com"/ibm/ws/webcontainer/srt/SRTRequestContext...The solution was to clear the WebSphere class caches as described in this IBM technote http://www-01.ibm.com/support/docview.wss?uid=swg21607887