When activating the sliding function of the keyboard, do you have abnormal resistence to the action you are attempting to take? (do you have to force it to extract / retract when you decide to undertake that action. Here is the service manual for the HTC Touch Pro. You can see clearly that the bidirectional cams are NOT supposed to be interfering with the operation of the display.
HTC Touch Pro Service Manual:
http://www.4shared.com/file/11329434...01_Dec_08.html