I don't see, however, how Remote Buddy could cause any hangs of Front 
Row where not even the keyboard would work, though. All Remote Buddy 
does to control Front Row is emulate key presses using the OS X 
"remote desktop" API and that's really it.

Except for the driver, which needs to be in /System/Library/ 
Extensions/, and which Remote Buddy is taking special care of, Remote 
Buddy is self-contained and doesn't modify or install any files in 
your system. So upgrading vs. a fresh install shouldn't make any 
difference.

The only problem that I can imagine that could make Remote Buddy hang 
(but not Front Row) is AppleScript-related. Did you rename any of the 
apps installed on that system (like f.ex. iTunes.app to iTunes 
7.6.app) or add custom actions containing AppleScript on the computer 
you experience the problem with?

It might be worth a try to quit Remote Buddy, move the preferences 
files in ~/Library/Preferences/com.iospirit.*emote*uddy* to another 
place (=> effectively putting everything back to default settings), 
launch Remote Buddy and see if you experience any hangs of Remote 
Buddy when entering Front Row after that.

If you experience a hang of Remote Buddy, please use Activity 
Monitor.app to make a sample, so I can have a look at what is going on 
inside Remote Buddy.

Btw, are you using the latest version of Remote Buddy?

Best regards, 
Felix Schwarz