If you've experienced the same problem as I did with the A.C short key for "Drag a Copy" not functioning while the Mac OSX "Dock" kept on popping up and down instead, then here is one solution to your problem:
Check off the Dock short key command settings under the Apple Menu/System Pref's/Keyboard & Mouse Set's/Short key commands tab.
You will find the Dock's check box towards the end of the list.
