Debugging VFP COM servers is no longer hard and there's really no need to use text files any more(maybe for quick and dirty stuff) - check out:
http://www.theproblemsolver.nl/aspdevelopmentanddebugging/index.htm

>>Have you tried to log that to a .txt, for example, to see what's arriving. >Debugging DLLs is hard, and that's one of the things I do often. I >basically use a TXT as my "debugout".
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>>The question is: Can you pass an XML string to an ASP and have a VFP DLL process it?
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>Yes you can. There must be some tiny detail there.
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>>There's a side issue here too. Despite all my attempts to make sure that the object reference gets released, it doesn't. I've got to re-boot to re-build the DLL. Anyone have a clue about this?
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>The DLL is cached inside IIS. You have two ways:
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>The hard one is to open a CMD window ans issue IISRESET. That woudl reset the whole IIS -not very elegant for a production server.
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>The second one is to put your DLL into COM+. Then the only thing you have to do is stop that single package, install the new version, and that's all.
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>Hope this helps,