First, have you tried the debugger that comes with VFP 5/6/7? It's a substantial improvement over FPx2x's capabilities. Also, I believe, if the first thing you need is a debugger, then you need to get some basic training in VFP. There are a number of threads here that have recommended MS, and third-party tutorials, books, magazines, conferences and courses (on-line, video tape, self-learning and with live instructors).
When you have specific questions, I sure many of them can be answered here (or already have been) or on the other peer-to-peer support groups.
Rick