I think you need to seriously think about what to do. If you have to use Refox and don't have the source code, you probably don't have the documentation, and are working on an obsolete program designed for a out of date platform. Unless you are just trying to make a minor change, you are probably better off starting from scratch and using the database as a starting point. If you were supposed to have th source code, try finding and sueing the programmer. If you weren't supposed to have the source code, then by reverse engineering the code, you are probably in violation of the contract with the programmer and also, he may have made the source code locked against Refox.
I was faced with a similar problem last year, where the customer had source files for part of the system, but they were incomplete and out of date. The system was written for Visual Foxpro, but I could tell that the programmer did not know how to use VFP, and was programming as if it were Foxpro DOS. The truthe was that the code garbage, but actually worked [sort of]
The customer wanted to make minor changes which he thought would cost a couple of thousand dollars. I quoted him a minimum of $10,000, just to change one line, since I was working with a total unknown environment, and would have to spend most of my time doing detective work in the existing system. Also I would not guarantee anything in this type of situation. The client could not go after the programmer for damages, since the programmer had died.
In the end he opted for a major rewrite with enhancements, this will cost him $30,000 to $70,000.