[rules-users] RPC call exception with drools guvnor

Hi, I use drools guvnor first version 5.1.0, but now I have to use 5.0.1. On the PC, it has to work on, the following error is produced, when I enter the drools webpage: 22.04.2010 14:24:03 org.apache.catalina.core.ApplicationContext log SCHWERWIEGEND: Exception while dispatching incoming RPC call java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 at java.util.ArrayList.RangeCheck(ArrayList.java:547) at java.util.ArrayList.get(ArrayList.java:322) at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.extract( ServerSerializationStreamReader.java:617) at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.readInt( ServerSerializationStreamReader.java:432) at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader.prepar eToRead(AbstractSerializationStreamReader.java:38) at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.prepareT oRead(ServerSerializationStreamReader.java:383) at com.google.gwt.user.server.rpc.RPC.decodeRequest(RPC.java:234) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServic eServlet.java:163) at com.google.gwt.user.server.rpc.RemoteServiceServlet.doPost(RemoteServiceServ let.java:86) at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application FilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh ain.java:206) at org.jboss.seam.web.ContextFilter$1.process(ContextFilter.java:42) at org.jboss.seam.servlet.ContextualHttpServletRequest.run(ContextualHttpServle tRequest.java:53) at org.jboss.seam.web.ContextFilter.doFilter(ContextFilter.java:37) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application FilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh ain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.ja va:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.ja va:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128 ) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102 ) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java :109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http 11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454) at java.lang.Thread.run(Thread.java:619) That computer has Windows XP Prof SP3, Tomcat 6.0.20, Java jdk 6.0 update 17. The same error occurs with the jboss standalone. Version 5.1.0 works fine. On another computer, that is configured nearly the same (WinXP prof SP3, Tomcat 6.0.20, java jdk 6.0 update 7) all works fine. Maybe someone can even give me an advise, what could be the problem, or maybe have a solution. Kind regards, Dominik