k3b won't preview MP3s when creating audio project

[kortsen]

k3b has a feature when creating audio projects to preview MP3s. You should be able to hilite a track in the project track list and click the play button above the track list window. What I get is an error message popping up.

http://lars.kortsen.googlepages.com/k3b.jpg

My Googling so far has led me to check (and confirm) that artsd is running and kdebase-kio-plugins is installed.

[kortsen]

This problem seems to be related to Xfce (Xubuntu), but with a twist. I just tried an experiment. I logged out of my Xfce session and opened a KDE session. I launched k3b and it happily played previews. I then closed the KDE session and logged back in to an Xfce session. THIS TIME kde played previews. I then reset the computer and booted into an Xfce session. No previews again.