500 Error (java.lang.Exception) while doing a quick search

Fisheye Version:
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FE2.5.3 (20110328062424 2011-03-28)

Error message:
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"Your request was unable to be processed
java.lang.Exception -"

Log output (I attached the complete file):
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2011-12-09 12:14:21,640 INFO [btpool0-127 ] fisheye.app TotalityFilter-logExceptionDetails - Exception "java.lang.Exception" (javax.servlet.ServletException) while processing "/qsearch" (Referer:"http://XXX.XX.XX.XXX:8060/browse")
javax.servlet.ServletException: java.lang.Exception
at com.opensymphony.webwork.dispatcher.DispatcherUtils.serviceAction(DispatcherUtils.java:284)
at com.opensymphony.webwork.dispatcher.ServletDispatcher.service(ServletDispatcher.java:111)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)

....
....
Caused by: java.lang.Exception
at com.atlassian.fisheye.quicksearch.action.QuickSearchAction.execute(QuickSearchAction.java:107)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
....
....