Hi, I need help!.

I have a client which uses an ODBC driver to connect to a Progress DB.
The driver is Open Link Lite and the Progress DB version is 7.

Sometimes, an error happens, this is the message:

"[OpenLink][ODBC][Progress Server]Stale request handle. Request was not opened or has been closed. (1253)".

The scenario is this: the client program tries to execute 10 queries, but two or three of them return that error message. The sintax of all queries is equal, the query is like this: "Select part from tbl_parts where partId = 'variable'".

What could be happening? why this error occurs?
and the most important, what to do to solve it?