I think the jar file is set right otherwise he wud have got a NamingNotFound exception. I guess its a problem with the deployment. Might be that he did not specify the Home interface correctly while deployment. Jai try that. Try redeploying and make sure u specify the home and component interfaces correctly.
Also as a general case make sure that ur paths are set correctly. use this link below http://www.oreilly.com/catalog/hfjejb/errata/hfjejb.help
Sudhir V<br />(SCJP 1.2, SCWCD, OCA, SCBCD)