I'm seeing the following error after an intensive burst of activity
from the clients:

ISC ERROR MESSAGE:
Dynamic SQL Error
SQL error code = -901
invalid transaction handle (expecting explicit transaction start)

STATEMENT:
TIBOInternalDataset: "dmHost_6.DSModule.tblWebUser.<TIBOInternalDatas
et>."


Once one client runs into this error, all the rest of the client
follows. Any requests from the client will continue to result in the
exception above.

I'm running a MIDAS-like middle tier application server where the
server has 8 threads and thus, 8 connections to the database through
IBO.

Using the implicit transaction has worked flawlessly when there is
little activity. Once the activity goes up, we keep seeing errors
such as the above.

I would be very grateful if someone can tell me when an explicit
transaction is required, and when I can rely on the implicit
transaction (as suggested by the IBO help file) -- and why does the
exception only happen when the activity goes up (we monitored the
activity through a log file from our MIDAS-like server).

Configuration of IBO version 4.5.Ai:

TIBTable with TIB_Session, TIB_Connection and TIB_Transaction

TIB_Transaction is set such as:
ServerAutoCommit = false;
AutoCommit = false;
Isolation = tiCommitted;

As for TIB_Connection:
Protocol = cpTCP_IP;

IDE: C++ Builder 6 with Update Pack 4 and latest ilink32.

Firebird Version: 1.5.2 super server.

Thanks.