I'm an Ubuntu user (Dapper Drake 6.06 up to date).
I encounter this trouble only since I've installed
Dapper Drake). I've just installed Kopete 0.11.92 (0.12
beta 1) and it doesn't resolve the trouble.
The title of the main window must be « Kopete » but it
is replaced by %c (often after a reboot). I can
temporarely fix it by reinstalling kopete. Very
annoying since it happens everyday.