Do you've declaration for C++ or VB for this DLL? Can you post it?
>
>from VB6:
>

Public Declare Function BUICScan& Lib "BUICAP32.DLL" 
(ByVal iJob&, ByVal lpFront$, ByVal FLen$, ByVal lpBack$, 
ByVal BLen$, ByVal LpCode$, ByVal LpLen$)

With my limited VB knowledge, VFP declaration seem to be correct. Are all those input parameters or some of the are output ? Do you have sample call in VB?