I found the problem! Somehow the following registry entry had incorrect data:

HKEY_CLASSES_ROOT - VisualFoxProRuntime.6 - shell - open - command

the data was "%s\VFP60.DLL %%1"

I changed it to "C:\WinNT\System32\vfpr.dll"

This has corrected the problem. I also found out that around the same time I first encountered this problem, our network "burped" which could have been the reason why all this happened in the first place. Can't think of anything else that would cause such a weird problem.

Hopefully this will help someone who may encounter a similiar problem.

Here's a recap:
The things I tried prior to making the correction to the registry:

1) Created a run-time only setup and ran it.
2) Tried re-registering the vfp6r.dll and vfp6run.exe.
3) Reinstalled VS SP3.
4) Uninstalled/reinstalled VFP6 and ran VS SP3.

None of the above resolved the problem. I copied all of the VFP6 runtime files to the same directory as the EXE and the EXE would run. Removed the runtime files from the EXE directory and the EXE would not run, even though the runtime files were still located in the windows system directory.

Thanks to all who responded...

Whew, glad that's over with!

James