Report Error

I'm getting this when I try to view a report:

HTTP Status 500 -

type Exception report

message

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

exception

javax.servlet.ServletException: Servlet execution threw an exception
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)

root cause

java.lang.NoClassDefFoundError
com.adventnet.servicedesk.helpdesk.reports.utils.ChartGenerator.generate3DPieChart(ChartGenerator.java:270)
com.adventnet.servicedesk.helpdesk.reports.utils.CustomReportDesigner.generateChart(CustomReportDesigner.java:3221)
com.adventnet.servicedesk.helpdesk.reports.utils.CustomReportDesigner.generateReport(CustomReportDesigner.java:5223)
com.adventnet.servicedesk.helpdesk.reports.utils.CustomReportDesigner.generateReportCompiledJasper(CustomReportDesigner.java:4902)
com.adventnet.servicedesk.reports.helpdesk.action.CustomReportHandler.execute(CustomReportHandler.java:650)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
javax.servlet.http.HttpServlet.service(HttpServlet.java:697)
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.