Weird keyboard CAPS-Lock reverse Bug

[Oopsy!]

Hi. I really have searched for this on the net and here, so please don't kill me if it's old news.

When playing BZ Flag (and only BZ Flag) sometimes the CAPS-Lock status of the keyboard is reversed.
Meaning: CAPS-Lock OFF = all UPPER case letters,
CAPS-Lock ON = all lower case letters.

The weird part is, it stays that way when exiting to Windows XP. I have to restart.

Now, this really absolutely only happens sporadically when playing BZ Flag.

Any Ideas?

My System:
P4 3,2 GHz
Asus P5GD2
1GB RAM
Windows XP Pro SP2 + patches
NVidia 6600 GT PCIe
Keyboard PS/2
Mouse USB
Logitech Rumblepad

Thx!