My guess would be you've disabled UAC or are logged in as admin, while your friend is using a normal user account to run your software. The debug privilege is by default only enabled for the admin user group.
The next possibility would be that one of you is running the software inside a virtual machine and the software takes a different execution path depending on the environment either for compatibility or protection reasons.
It also could be that some IPS is running on your friend's system blocking this kind of action. Or it's some poorly configured anti-virus solution. If it really is the former, he shouldn't be running some software from some friend anyways.
