Hei thanks for your help! I couldn't figure it out. However, I created a new user. It's not a nice way but finally brought the menuback.
Oh I'm sorry. It's KDE 3.3. In ".locale" are some files but all of them have the suffix .desktop
Hei! I accidently deleted the content of my K Menu by using KDE Menu Editor. Is there a way to restore the default settings for this user? Thx