With regards to your digitizing problems....
I have workied with Grass v.digit on both Calcomp and Altek digitizers. Both have at one time or another, given me similar problems. I would first try actually holding the puck on the digitizer (in any active area) before you hit return given the prompt: "Shall we continue"..or whatever it says.
This always worked for us. It's a strange quirk, but it did seem to solve our problem.
Good Luck.
-Eric Lambert
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Eric Lambert Lab: (217) 333-5919
Illinois Natural History Survey
607 E. Peabody Drive
Champaign, IL 61802