I got a used Sony Vaio E-Series [not my first choice, but what was available] and installed Wubi on it. I started with Ubuntu 10.10 and went on to 11.04 before reinstalling 10.10 in my attempts to fix this bug.
The machine has an ALPS Glidepoint trackpad in front of the keyboard, and it is hard to avoid the trackpad while typing.
The mouse wheel becomes unresponsive if the mouse is moving (turning) simultaneously. In terms of game play... you can't switch weapons while moving the mouse. You must stop moving the mouse in order to be able to switch weapons.
I heard that this was a know bug an easy fix... but that was months ago. I forgot where I heard this.