Thank you for your help so far!
Did you try using the .cc file aminchew posted in this thread?
Yes, I have just tried that code and it is unresponsive as well
What do you have your AC adapter plugged into?
A wall outlet (no power conditioner/surge strip). If it was a power issue, other codes would be affected though, right?
Are you sending any other commands to the Pro before you send the PowerOff command? I know with Harmony remotes by default it tries to send the stop command before sending the power off command and that causes problems.
No, this is the only code I test. I am only testing the individual codes at the moment, so there are no macros (I only created the Power Off macro as a temporary replacement).