Just curious, but what command did you issue to attempt the removal?
The correct syntax is
ipkg remove mt-daapd
If that is the command you used, you may have to resort to manual removal. The installed files and their respective paths are listed on the package page for mt-daapd at the slug site – about halfway down the page.
Remember to backup your configuration file.
Should you need to resort to manual removal, you will likely need to force a subsequent installation.