Working here too...Although I had to look to find it in the KDE menu, I always used the terminal version of it.
The clown of usability, I found that out the hard way.
See if you can spot the problem:
# kernel-remover -h
-F parameter use parameter as the graphical frontend
one of text | dialog | kdialog | zenity
-f proceed without asking, do complete cleanup
-h show this usage