Customer is with Mac 10.7.5 and Statistics 21, which works fine. But there is always an error (shown below) when opening the Help...Tutorial
"HTTP ERROR: 500
Plug-in org.eclipse.help.webapp was unable to load class org.eclipse.help.internal.webapp.servlet.ContentServlet "
Resolving the problem
The customer is with administrator account and error existed in IE, Safari and FireFox.
Creating a new account with administrator privilege resolved this issue.