Bug#477795: Additional information and maybe workaround
I have just renamed ~/.kde/share/apps/kopete and suddenly I could open the
settings again. The problem seems to be related to an entry in this
directory. Since the configuration is stored in another directory you would
only loose your chat history (or rather complicate the access to it).
Maybe the severity of this bug could be adjusted to "normal", since the
solution is pretty straight forward and I suppose it is a rather uncommon