Probably just your download failed. Try to download the ipkg again, probably directly from the slug.
would fetch the current latest nightly to the directory where you’re at, with telnet on the slug.
So basically just log on and issue the above command, followed by:
ipkg install http://nightlies.mt-daapd.org/dl.php?FILE=mt-daapd_svn-1463-1_armeb.ipk
that should do the trick, given your slug has access to the internet, that is. 🙂