> But the same error always happens just after the rollback within
> JOnAS. So, I try to use the old InterServer/InterClient again (with
> the same configuration: Firebird 1.5 and JOnAS 3.1). And it works
> smoothly. I also can see from the log file that the same rollbacks
> happened within JOnAS but no crash within the Firebird DBMS. So I
> think this must be the problem of JayBird as I only replaced the
> JayBird with the InterServer/InterClient.

Can you try JayBird RC2 in type 2 mode, so it uses fbclient.dll to
access the server?

Thanks!
Roman