If touch isn't working on your MTi1. Open the Multi-Touch Platform and be sure the Serial Number of the unit is showing.
If not click "apple" logo on the top left of the menu bar and go to "About This Mac" then select "System Report" and under the USB tab the touch controller should be showing as "PQLabs Touch Controller.
If the usb is not showing in the System Profile, try to plug direct into the computer, or if it is direct into the computer try a different USB port. If that doesn't help, please try a different USB cable.