Can't change file association for wm files

[komodo <komodo@uvt.cz>]

Hi

There is one strange thing, i can't change file association for files with wm 
extension.
From systemsettings i change to mplayer, then click to Apply, it shows Aplying 
settings window, but after this it return to previous settings. 
And it's interresting that default app for wm is amarok.

I have tried made this change from Dolphin, but there was the same behaviour.

All other associations works, except wm.

Is this KDE or Debian bug, or something on my side ?

My system, Debian Testing with KDE 4.2.2

Thanks

Martin