Are you running a WCF or ASMX service on the server?

If so, be aware that this will cause you some serious grief as these services require MTA COM components. VFP is STA. Although things might appear to work under low load or single user testing, with simultaneous users you will see crashes.

There are some ugly workarounds for this. More info can be found here:
http://www.west-wind.com/weblog/posts/2012/Sep/18/Creating-STA-COM-compatible-ASPNET-Applications

The only in the box 'supported' safe way to run VFP COM components natively in ASP.NET is by using WebForms and AspCompate="true".

+++ Rick ---

>I have an ASP.NET web service wrapper for some VFP functions that I have developed. In my development machine using Visual Studio 2008 (and have now tried VS 2013 preview) and the internal web server, all runs well. When I deploy my web service to a production server, even the HelloWorld function returns an HTTP 500. It seems that as soon as I have a DLL referenced in my web service, the whole project dumps. Considering this works in the local Visual Studio web server/browser, shouldn't it work on the IIS 7 server as well?
>
>I have tried the following:
>
>1. Successfully registered the amsync_web.dll with regsvr32 on the server in the development directory. I get the HTTP 500
> *note* that there is also an interop.amsync_web.dll in the bin directory of the web folder.
>2. Removed the interop.amsync_web.dll from the bin folder. Now I get a compilation error BC30002: type 'amsync_web.amsync_web' is not defined.
>3. Fine, I unregistered the development copy of the dll and tried to register the interop copy in the bin directory. Get ugly error and unable to register.
>
>Can anyone help steer me on what I thought should be a fairly straightforward process? Much gratitude to anyone who can keep me from wasting any more hours of time on this...