Are you running FoxWeb as a system service?  If yes, does your page work when you run it as a reguar application?  In this case, the problem is probably related to the fact that the service user does not have access to that particular registry key.  You can fix this by giving more rights to the FoxWeb service user.

 

If the problem is not related to user rights, then it is probably related to a problem with your code.  Try running the same registry update code in a regular VFP program.