Can't change tones on C500

[Guest sfxman]

Hi,

i have a problem with my new C500, it seems i can't change the ringtones.

I managed to change it yesterday (to another builtin one) but now, whenever i go in the sound window, and click on 'done', nothing happens, i can only quit this window by clicking cancel ...

ideas anyone ???

Matt

EDIT : i 'solved' this by doing a soft (?) reset from the accessories menu, but this is still very strange/annoying ...