Update Internet Explorer, the Office 2000 CD contains a newer version than you have, and you most likely answered "no" to it asking you to upgrade during office install. A certain .DLL (can't remember which one, browser related) will initiate office install (or whatever else prompted the dialogue to upgrade IE) everytime it's used if it thinks it needs a newer IE.
Something in Gnotella must call that .dll. This has been confirmed a "feature" of this .dll, not a bug
according to Micro$oft.
in any case, Gnotella isn't to blame, they're just calling a rude Windows library you happen to have under conditions you also happen to have.
Once you have installed the new IE5.5sp2/or 6preview, it'd be a good idea to also install Office2k sp2 patch, as this fixes that bug*cough*feature, so that future software won't do the same thing.