Oh, right, forgot the basics
OS: Windows XP SP3
OD Version: 1.9.0.535(according to the *.exe)
Windows Firewall: active (disabling doesn't help)
Security Software: Avira Anti-Virus 10 (the docklet already stopped working while I still had Version 9, worked fine before along with Avira though)
Removing and re"installing" the docklet didn't help either (I didn't re-install ObjectDock though)
EDIT: I tried the updated docklet version over here as well as the previous version which I still had on hd and neither of them worked.
Since I can't really tell when exactly it stopped working