Maybe not the best solution, but try this:

When the file has been uploaded, set a flag somehow (Record in a SQL/VFP table) saying that the file is avilable.

Then just have a normal VFP application running on the server, which check the flag/table/record now and then to see if any new files has been uploaded and then execute the program for the available files. This way you can bypass ASP and a DLL to do the work.

Hope that helps,