I got around this error by removing libunistring and compiling this package from source.

The problems I have been having so far are that for some of my mp3 files, the tags aren't read.
Watching the program running using forked-daapd -fd 3, the songs that don't have tags show this:

ffmpeg: ID3v2.4 tag skipped, cannot handle unsynchronization

I am using the ffmpeg compiled from source on ubuntu 10.04 server amd64.
when I was running mt-daapd, it processed all of the tags correctly

Another issue I had was when I used the prebuild forked-daapd for debain on ubuntu, I could detect my AirPort Express and connect to it after I rebooted it through remote on iPhone (otherwise it would not connect)
On the version I built, the APE was not discovered.

Any hints would be appreciated,
I'll try rebuilding today.