Error Editing Time Entries

I upgraded to 6004. I receive the following error when updating time entries. The error occurs when the <save> button is pressed. Need help ASAP since my people can't enter time.....

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

java.lang.NullPointerException
org.apache.jsp.workorder.AddBilling_jsp._jspService(AddBilling_jsp.java:215)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1069)
org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:455)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:279)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
com.adventnet.servicedesk.filter.EncodingFilter.doFilter(EncodingFilter.java:66)
com.adventnet.authentication.ContextChangeDetector.doFilter(ContextChangeDetector.java:100)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:75)

note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.