Happy Xmas to everybody !!!!!

Login problems R12

On our R12 eBS environment we are facing a problem when loggin in. It does not happen all the time, because we use more then one web node (loadbalancer), but when trying to acces the login page the following error is shown...

"Unable to generate forwarding URL. Exception: oracle.apps.fnd.cache.CacheException"

or a blank page is shown instead of the login page. In the applications.log file ($INST_TOP/logs/ora/10.1.3/j2ee/oacore/oacore_default_group_1), I found the following error :

09/11/10 08:04:38.130 html: chain failed
javax.servlet.ServletException: java.lang.RuntimeException: Unable to create user session. Please contact your System Administrator.
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.EvermindPageContext.handlePageThrowable(EvermindPageContext.java:899)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.EvermindPageContext.handlePageException(EvermindPageContext.java:816)
at _AppsLocalLogin._jspService(_AppsLocalLogin.java:303)
at com.orionserver[Oracle Containers for J2EE 10g (10.1.3.4.0) ].http.OrionHttpJspPage.service(OrionHttpJspPage.java:59)
at oracle.jsp.runtimev2.JspPageTable.service(JspPageTable.java:379)
at oracle.jsp.runtimev2.JspServlet.internalService(JspServlet.java:594)
at oracle.jsp.runtimev2.JspServlet.service(JspServlet.java:518)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.ResourceFilterChain.doFilter(ResourceFilterChain.java:64)
at oracle.apps.jtf.base.session.ReleaseResFilter.doFilter(ReleaseResFilter.java:26)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.EvermindFilterChain.doFilter(EvermindFilterChain.java:15)
at oracle.apps.fnd.security.AppsServletFilter.doFilter(AppsServletFilter.java:318)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.java:621)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDispatcher.java:37 )
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.HttpRequestHandler.doProcessRequest(HttpRequestHandler.java:871)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:453)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.AJPRequestHandler.run(AJPRequestHandler.java:313)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.AJPRequestHandler.run(AJPRequestHandler.java:199)
at oracle.oc4j.network.ServerSocketReadHandler$SafeRunnable.run(ServerSocketReadHandler.java:260)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:303)
at java.lang.Thread.run(Thread.java:619)

Searching Metalink did not solve this. I could only find something about APPS_TS_ARCHIVE tablespace being full...
What could cause this problem in R12 ??

It seems it is unable to create a user session at that moment.