If I drag a file into audacious main window then popup says: Unable to play files. The following files could not be played. Please check that: 1. they are accessible. 2. you have enabled the media plugins required. If I drag a file into audacious playlist window then it works fine. Here are use flags that i used to emerge audacious: media-sound/audacious-1.1.0 USE="aac alsa arts esd gnome mmx mp3 nls oss vorbis wma -flac -jack -lirc -modplug -musepack -sid -sndfile -timidity"
Bugs in the software go upstream. Bugs in the packaging (ebuild!) go to the Gentoo bug tracker. Please try to file your bugs in the right place. I would suggest that you comment to upstream bug #532.