The current version of audacious (1.2.1) barfs on files with a \ in the name. For example, the file: Great Big Sea/Great Big Sea/01 - Great Big Sea\Gone By the Board.mp3 will end up in the playlist as 2 entries, Great Big Sea/Great Big Sea/01 - Great Big Sea and the second is Gone By the Board. The second entry points to a non-existant file, because audacious converted the \ to /, and then the player stops and complains that it doesn't know how to handle the filetype. The attached patch adds an option to the playlist prefs window to suppress this conversion, which makes it work for me. The default value is to leave the behaviour the same as it is currently.
Created attachment 102997 [details, diff] Patch to fix / conversion
<Osiris-1> Audacious: chainsaw * r3033 /trunk/audacious/ (6 files in 2 dirs): Allow \ to / conversion to be switched on & off, by external contributor Chris Kehler <cbkehler@sympatico.ca>. Your contribution has been merged upstream and will be in the next release. Please note that 1.2.2 is the current release of audacious, not 1.2.1 Thanks, it's not often that bug reports come with patches that apply without any effort. I'll wait a short while to see if I can accumulate other fixes before I roll a 1.2.2-r1 ebuild.
Your fix is available in 1.3.0_alpha1, which just hit portage.