Media Player Applet ask sometime for changing icon

Hi,

I use Ubuntu Hardy 32 bit on a laptop with NVidia QUADRO FX 1500M graphic card, proprietary drivers and Compiz enabled.
I use the last AWN build from PPA (827).

I have added the Media Player Applet and used it with different audio and video files. All function well, but a strange behavior with some video files. When I drag a video file over the Applet, the applet begin to play it correctly, but display a window that ask me to change the icon. I attach here the image of the window.

I have started AWN within a terminal and I can send you the message that is displayed in this case:
=============================================================
/home/nicola/Video
/usr/share/avant-window-navigator/applets/media-player/media_player.py:258: Warning: g_object_unref: assertion `G_IS_OBJECT (object)' failed
  gtk.main ()
=============================================================

If you want a video file that produce this problem you can download from here:
http://uploader.polorix.net//files/33/bugs/ATI-9700-animusic-Movie-v1.0.mpg