>Hi,
> I face ILLEGAL OPERATION / INVALID FAULT PAGE in my application. It doesn't happen everytime. Does it caused by my application ? How?
> I don't allocate/deallocate memory in my code. It just does normal data handling and serial port comm.
>
>Any ideas?
>
>Thank you

This happens when the program tries to access memory locations it's not supposed to. VFP is allocating/deallocating memory.