Version:           2.1.1 (using 4.2.90 (KDE 4.2.90 (KDE 4.3 Beta2)), 4.2.90-1.fc10 Fedora)
Compiler:          gcc
OS:                Linux (i686) release 2.6.29.4-75.fc10.i686

I have a partial backtrace for this but I think it's quite easy to reproduce so developers can get a more complete backtrace than mine.

The problem is that Amarok 2 cannot reproduce files with a sharp (#) in the name.
If you try to play one of those files Amarok will refuse to do so; if you put the file in the middle of a playlist you'll get a crash when you'll reach that file. Deleting the # from the filename makes the file behave normally (you can keep the # in the tag, the tag doesn't matter).

I report this because in Amarok 1.4 it worked just fine.

Please tell me if you can't get a complete backtrace.