Click the UPDD "Hand" icon up in the menu bar and check "Status" is set to handle monitor 1 OK. If it is showing "No Devices" then try a different USB port or USB Cable.
Lastly, be sure you have installed the correct touch driver for your type of Raven. Raven MTi1 uses Multi Touch Platform and Raven MTi2 uses UPDD. If the Multi-Touch Platform was accidentally installed on the MTi2 system download the installer on the bottom of this page and run the Multi-Touch Platform Un-installer.
If you are on MTi2, be sure UPDD TUIO is showing in the Menu Bar, as this is where Raven gets its touch info from.
If touch is working on the RAVEN but not on the desktop or on any other applications, be sure UPDD Gestures is open as this is where the operating system gets touch information from.