Hi Belasko44 and welcome to the forum.
How did you get your usb webcam to work? Did you use macam or ioxpert drivers?
There is another way to play with the plist files in your home/Library/Preferences, but you might mess up with your login data. However, since yahoo doesn'T save any history you won't mess up too much when you delete the plist or reinstall the software.
However, does it hurt that bad to get this error after you want to quit the application (or log out)?
iBook 600; 12''; 640mb; 8mb Rage; DVD-CDRW-Combo, 20GB
P4 1.6; 2x80GB Raid1 (file-server)
tiBook 1Ghz, Superdrive, 768MB, 64mb 9000, 60GB