GPF in IDAPI01.DLL at 001C:153C (vr 2.52)

We experiment a problem at some customer places.
We have a 16 bits program running 24/24 and sometimes, without reason, it
crash with a GPF in IDAPI01.DLL.
This only occurs with the SYBASE driver connected to a MSSQL server 7.0.
This occurs on NT 4 workstation and NT 4 server.
The program is certainly not in cause because it runs normally during
several hours or days and it runs correctly on more than 1500 other

Some idea ?
Flexsys Belgium sprl
Jacques Garcia Vazquez