I guess the problem is with the config file of kicker (kde panel). You can try the following:
1) goto the directory: ~/.kde/share/config/
rename the file "kickerrc" to something else.
Note: All your user configurations for your kde desktop is found in that directory. Good place to check things if you face more situations like this. However, if you play with those files, your personal preferences can be lost. In your case, for the kicker - child panel, applications, actions etc. on your panel - will be reset to default values.
2) goto the directory: ~/.kde/share/apps/
move the directory "kicker" to something else (this maynot be needed... ).
3) Restart kicker (type "kicker" from a terminal, or from the KDE-run-command utility)
Hope that helped