Error 500--Internal Server Error

Help new to this error: I'm soso on a computer and I'm trying to get to a wesite: http://www.sprint.com/pcsbusiness/support/downloads/items.jsp, and I'm getting this error i know it's gonna be simple but I not able to fix this any help please, I'm using windows xp I updated all that I could up date that I thought of ......................

Error 500--Internal Server Error
java.lang.NumberFormatException: null
at java.lang.Long.parseLong(Long.java:372)
at java.lang.Long.(Long.java:671)
at com.sprint.pcsbusiness.tags.PCSSoftwareTableTag.doEndTag(PCSSoftwareTableTag.java:39)
at jsp_servlet.support._downloads.items._jspService(_items.java:166)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:225)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:127)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:272)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:165)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3153)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:1973)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:1880)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1310)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:207)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:179)