I installed RadioTray in Lubuntu 12.04 (64bit) and it can't play radio streams. When a stream is started, it throws this notification:
> Radio Error gstplaysink.c(1906): gen_audio_chain ():/ > GstPlayBin2:player/GstPlaySink:playsink0
I can play all those streams from audacious and the browser itself (chrome).
I have been playing radio streams (shoutcast) for months and had been using streamtuner2 to find streams (but it has a sorting error that you cannot tell what stream will you end up listening to).
I also can watch videos with vlc and in youtube, etc.
Maybe it could be some plugins problem, but I can't find any logs.