It sounds like the first message under Vista is being caused by the tablet drivers failing to initialize, which is then causing the second message of ArtRage Wacom edition not recognizing that there is a tablet attached. (ArtRage Wacom edition will ONLY run if there is a Wacom tablet attached)
The most likely cause of the first message is that you dont have the latest drivers - double-check on the Wacom.com site that you have the latest drivers for Bamboo under Windows Vista.
You should have a Wacom tablet applet under the Windows Control panel. Test to see if that applet can find the tablet, and report pressure etc.
AndyRage's mantra for graphics engine code:
"Sure - how hard can it be?"