Problem with Wacom drivers

Recently, I migrated my Wacom Intuos from a computer with Win XP Home
(German, fully patched, no SP 3) to another computer with Win XP Home
(German, fully patched, no SP 3). The following error message migrated
with the tablet: "Fehler beim Verarbeiten von ...\decicerc ...
unexpected character'(', expected string constant - Schwerwiegender
Syntaxanalyefehler". But everything works fine, including pressure
sensitivity. In Configuration Dialog "Erweiterte Eingabegeräte", there
are a lot of funny characters after "WACOM Tablet".
It has the latest driver installed, 6.06-4aWindows_Wacom, for Intuos.
All in all, no problem, but a hint that something ist not perfect.

I use the latest available GIMP for Windows (version 2.4.6) - a
wonderful program ...

Now the real problem:
On my XP Home-computer I installed a Wacom Bamboo tablet - somewhat
larger, also with the latest driver: cons5.08-2a_int (it's a lower
driver series apparently because Bamboo is not a 'professional'
tablet). Initially, there was no pressure sensitivity; this works now
after re-installing the driver about 5 or 6 times ...   BUT the cursor
becomes very trembling, moves about in erratic fashion and so on.
After a certain time, pressing the <Win> key etc. etc., I can draw
with it for a while, then the wobbling starts over again.

This seems to be a problem of WACOM (?). Does anybody know about this ?