Make sure you have permissions - when you register make sure you Run As Administrator.

On Windows Vista/7/8 User Account Control effectively doesn't make you an Administrator even if you are part of the Administrator group until you explicitly elevate.

COM registration requires admin rights to write to the HKLM key in the registry.

+++ Rick ---

>I have just receive brand new Windows & Enterprise - 64 Bits. Have been installing old applications.
>
>I one of my project, I have the option to run a subroutine in Parallel. But when I attempt register the ParallelFox.exe (via Install.prg), I fails with a registration failed. Now, I have a similar machine and configuration at home, and it works fine. I even tried registering it in Administration mode, still fails.
>
>Any ides?