>At home on a machine with VFP 5.0a ,local data, I build an '.app' file. When I issue a 'SET STEP ON' I get a "FEATURE NOT AVAILABLE" error.
>
>However, at work with VFP5.0a installed , local data and using an '.app' file I issue 'SET STEP ON' and it activates the debugger with no problems.
>
>Why no errors at work? but errors on home machine?

The odds are that you're running under the runtime engine at home. You will get this exact error from the runtime. You can also get this error if you do not have the source in the same locations as on your development system at work, and the .app has been compiled encrypted.

If you have the development engine at home, it's possible that an install miscue could be causing the problem. Locate the VFP 5 development executable on your system. from a DOS prompt, run VFP with the /R command line option - this will reset the registry assignments to the settings for your development version.

I do not know if it will affect the otions subkey, which corresponds to the Tools/Option dialog settings. You could copy off the registry subkey you want to protect to a .REG file, which can be fired after letting VFP 5 fix itself.

For example, on my home system, I'd issue the following commands at a DOS prompt:

C:
CD "\Program Files\DevStudio\VFP
VFP /R