Version:           2.2.0 (using KDE 4.3.2)
Compiler:          gcc (Gentoo 4.3.2-r3 p1.6, pie-10.1.5) 4.3.2 
OS:                Linux
Installed from:    Gentoo Packages

Amarok stops or skips to the next track when trying to play a file that has a # in its search path. It is possible to view/edit ID3 track details in the file though. 

When trying to play the file "/mnt/hugestorage/Music/Bob Dylan/[1990] The Critics Choice #1/10 - Gates Of Eden.mp3" for example, 'amarok --debug' prints:

amarok:   [EngineController] [WARNING!] Phonon failed to play this URL. Error:  "19:42:59: input_file: File not found: >file://mnt/hugestorage/Music/Bob Dylan/[1990] The Critics Choice <
"

The file plays OK if one removes the #-character from the path.

With the # it plays in other players like xine-ui, mplayer and VLC.