Comment 2 for bug 94047

I had experienced an almost similar problem:

1) start playing an stream (playlist gets populated with stream)
2) stop
3) network settings change (get a new IP via dhcp or laptop hibernates and comes back up)
4) try to play the same item in *PLAYLIST*
           --> error
5) delete the contents of playlist
6) drag the stream back onto playlist
7) Amarok will play it with no issues

This makes me think it could also be KIOSlave problem. Probably this is more of an Amarok issue than a Kubuntu issue.