Might the reason for your issues be this (as stated in the installer)
Important note for Final Cut Pro HD Users
You must first disable “keyboard Navigation” in Mac OS X before using. the “play rate transport controls” for Final Cut HD. Here is how you do this:
1. In the Apple, menu select “System Preferences”.
2. Select the “keyboard and Mouse” icon.
3. Unselect “Keyboard Navigation”.
Users of earlier versions of Final Cut Pro will need go to www.contourdesign.com/shuttlepro/shuttle_downloads.htm, and download settings Final Cut Pro Edit/ Viewer and Final Cut Pro Edit/ Timeline.