The Internet Transaction Server failed to generate the response for current

We refresh our EBP system for development clients after system packs. We are on EBP 4.0, R/3 4.6C and we are on classical scenario. Before system packs we were using MED-400 as EBP system and MD1-400 as R/3 system. Now we are using EBP-500 as EBP system and MD1-500 as R/3 system. We did our clients refresh steps but we are missing something. When I shop thro' web gui we are getting following error message.

Interpreter Failed

The Internet Transaction Server failed to generate the response for current request.

Please contact the system administrator.

Internal error code: 0x2101

I would appreciate if someone can help me to resolve this issue.

Thanks in advance!

Mrudula