If you're talking about recompiling that VFP mtdll after it's been run from ASP.NET, this has been a nagging question for a while now and I would like to see a solution too. While I can easily "Unload" a vfp mtdll application that's been called from ASP, without disturbing anything else, I get your same error after that same vfp mtdll has been called from ASP.NET. Unloading would be the smoothest, but, the only solution right now is to stop/start IIS (iisrestart).
If you mean you can run your vfp mtdll only once from ASP.NET, then probably you don't have a proper setup. See the source code for ActiveVFP and the ASP.NET demo at http://www.activevfp.com/avfpdemo2/default.aspx .
>I use a VFP8 interop DLL. I can run this web site once, close it, build and run it again without touching anything on my machine and all the sudden get an access denied error, cannot access tcweb.interop.dll which is the DLL in question. What's the deal?