Hi,
a small, but annoying problem: I cannot use the Trim Right (1 or 10 frames) keyboard buttons, neither can i assign them to other keys (precisely, i can do that, but i when i press them, i hear the mac-you-are-doing-something-wrong-sound). I changed the keyboard layout from german to us, the problem still exists.
Does anyone experiences the same problem or knows a solution? 

Thanks! jub

Which keys do you have them assigned to?  ">" and "?" are default.  Are you using those?

i am using the default layout on an USB logic keyboard, with german keys. So on my keyboard its "." and "-" (the location is equal to yours ">" and "?"). Strange thing is, that the command right trim does not function at all, neither on the avid GUI keyboard nor on other keys (i drag and drop the command trim right on "q").

Have you tried a new Avid user?  Sounds like it could be corrupted.

same dilemma with a new user profile. Are there other preference files? (i have deleted all avid users in shared users).Perhaps a problem with 10.7.4?

The problem was in front of the screen (stupid me, learn the basics!).
Changing an edit to the left or right is working (dual-roller trim). When i disable smart tools and select the red tool i am able to move the clip. The term trim was misleading - sorry - i picked it beacuse of the key names without thinking. 
Kevin, thank you very much! 

Glad you figured it out!

DUDE! this has been bothering me for over a year. I finally decided to search for the answer. Voila! Thnx. 

But the problem still exists in effect mode when you try to move sliders with the trim right 10 frames. The others work.

Wow. I have been cutting on Avid for over a year now and this didn't happen until today. It was making me crazy, until I found your solution. However, when I have smart tools selected they have all always been on. Not sure what's up. But, if yellow/insert segment is off, It's fine. Thanks for the solution. But, hmmm....