先天一气混沌元胎:也免出现此类情况是什么原因？

500 Servlet Exception
java.lang.NullPointerException
at com.chinaren.club.score.Upgrade.getLeastGrade(Upgrade.java:108)
at com.chinaren.club.score.Upgrade.getGradeRank(Upgrade.java:99)
at _jsp._user._profile__jsp._jspService(/usr/local/resin/htdocs/club_jsp/user/profile.jsp:116)
at com.caucho.jsp.JavaPage.service(JavaPage.java:87)
at com.caucho.jsp.JavaPage.subservice(JavaPage.java:81)
at com.caucho.jsp.Page.service(Page.java:410)
at com.caucho.server.http.Invocation.service(Invocation.java:319)
at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:121)
at com.caucho.server.http.RunnerRequest.handleRequest(RunnerRequest.java:333)
at com.caucho.server.http.RunnerRequest.handleConnection(RunnerRequest.java:266)
at com.caucho.server.TcpConnection.run(TcpConnection.java:140)
at java.lang.Thread.run(Thread.java:534)

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Resin 1.2.8 (built Wed Jul 11 11:14:00 PDT 2001)

能否用专业术语介绍一下上面的情况，谢谢