Is this an xa-driver (supporting two phase commits, supplying an xadatasource)?
Can you find out from the driver vendor if they require a specific XId implementation for their XAResource? Despite this guaranteeing inoperability with other dbs, at least Oracle does this with their xa driver.
Maybe show your jboss.jcml config?? This might be a good idea in any case.
You need the latest Opta2000 driver!
Version 4.11 has the Xid error fixed.