Testing sounds from the GNOME control Panel does not work until you restart X (doesn't state that anywhere): execing: bell-properties-capplet --id=9 --xid=29361396 Priority 50 : Registering Id = 117f000001000092217047500000013250015 sh: -c' requires an argument The above was displayed after switching back to the virtual console that was running x.
This bug is four months old. Please try the latest GNOME and open a new bug if the problem still exists.