I have a C++ exe that calls a function in a PowerBuilder non-visual userobject.

I'm getting a valid system error and despite using the HasExceptionThrown and ClearException session methods in the C++ and having code in the systemerror event of the PowerBuilder application object, the system error MessageBox is displayed.

Having a random MessageBox appearing is a problem because the program is running unattended.

What do I need to do to definitely prevent the system error MessageBox from appearing?