Directory Name is Invalid

[drumthrasher]

I've noticed that every program that I have to run as administrator THAT ISNT IN C:\Program Files, I get a 'Directory Name is Invalid' error, even for programs that are on my secondary hard drive.

But if I were to put them in Program Files then it would work.
Maybe this has something to do with UAC?

EDIT: THIS IS PISSING ME THE HELL OFF!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I've disabled UAC, restarted, same thing! Nothing new was installed!