1. Close TntMPD.
2. Delete "TntMPD.app" from the "Applications" folder.
3. Delete the folder: "Users / (your name) / Library / Application Support / TntWare / TntMPD / SavedSettings"
(To get to the Library folder on Mac OS X Lion - 10.7):
Hold down the Option key, and click the "Go" menu in Finder, and then click on the "Library" menu.)
4. Reinstall TntMPD from this download:
http://www.tntware.com/tntmpd/downloads/p/14018.aspx