accessing problem for my case, try yours, guys

when I log in, it showed like this
500 Servlet Exception
java.lang.NullPointerException
at gov.inscri.common.action.LogonAction.perform(Unknown Source)
at org.apache.struts.action.Action.execute(Action.java:415)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:480)
at gov.inscri.CrisRequestProcessor.processActionPerform(Unknown Source)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1420)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:520)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at com.caucho.server.http.FilterChainServlet.doFilter(FilterChainServlet.java:96)
at com.caucho.server.http.Invocation.service(Invocation.java:315)
at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
at com.caucho.server.http.RunnerRequest.handleRequest(RunnerRequest.java:346)
at com.caucho.server.http.RunnerRequest.handleConnection(RunnerRequest.java:274)
at com.caucho.server.TcpConnection.run(TcpConnection.java:139)
at java.lang.Thread.run(Thread.java:534)