I think that one clue might be the line in the output you first posted:
“AttributeError: ‘UserPreferencesInput’ object has no attribute ‘invert_mouse_wheel_zoom’”
I remember with my XP experience,
(yeah, I actually DO have, and Have had, windows OS’s, Do know what I’m talking about, AND I even have testified in court - many years ago - on Microsoft’s behalf … for which I am now terribly sorry. but thats a story for another day/thread/and forum.),
that I was clumsy enough to constantly get some of their things like ‘Sticky Keys’ turned on and that the special needs, or just user customizations, really screwed with some of my programs.
So, we have to ask if there is any Mouse related changes you remember making when this all started?
You mentioned that you had trouble with installing your Wacom,
(I just got a bamboo Wacom and it put a damned on screen keyboard on my Vista sign in screen… I have No idea how to remove it, I just live with it when ever I use that OS. It actually works better on my main Linux OS though it was harder to set up),
That Waycom might be a place to start investigating since we have dispensed with the normal mal-ware issues windows (especialy XP) is a magnet for.
Did you get the proper Wacom Drivers for XP installed and up to date?
Is there some tablet/mouse functions that might be turned around, (or, like I did once, is something sitting on your wacom or another mouse that’s plugged in. it would be so nice if it were That easy!).
Let us know your progress Evaler.