HI Raaj,
You would require the jars files listed under 'BusinessObjects Enterprise Java SDK', 'Viewers Java SDK', 'Report Application Server Java SDK ', which is listed under the developers guide.
Also try to open you report using the attached sample.
Additionally you would require the crystalreportsviewer12 folder in your applications context, which you can find from the installation directory of BusinessObjects.
<BusinessObjects Install directory>/Business Objects/Common/4.0
You would also need to configure your web.xml so that the viewer can be invoked.
The configuartions can be found from the developers guide under'configure your web.xml' section.
Hope it helps.
Thanks,
Prithvi