>I have tried sending 0, "0", and CHR(0), but I always get an "Invalid Handle" error returned from the DLL function. I am not a C programmer, but the type of parameter I am trying to send to the function is defined as "typedef void *CDK_HANDLE" in the header file. I just need to be able to create a valid parameter to send to the function from VFP.

What's the C DLL declaration look like? That'll probably answer the question.