Birt Chart Bar Display Error in Web Project.

[vinaychada]

i designed bar chart ..before intgration its working.
but when i integrate in web project on windows its working but when i try on aix server bar chart in not displaying instead a pop window is showing a class cast exception i.e no class found error.but no stack track get displayed.
is some other configuration required for aix server.
plz tell me its very urgent.