PROBLEM CONNECTING IR WITH ESSBASE

Hi there, Im trying to make a connection of Interactive Reporting with my Essbase server, but I'm getting the next error message: Undefined Exception in , line-1 system stack. trace unavailable.
FYI IR is working fine if I connect to a SQL server DB.

I found in the Oracle forum that this problem was because of the arborpath was wrong, but mine is OK.

Any Ideas??

Thanks in advance.

Victor