After application first start must be set at least location of one player. Winamp will be found automatically, if properly installed (associated with media files). Path to media files must be set after program launch from program menu ("Settings" - Media Files Setting).
.INI file (mp3man32.ini) location: by default in MP3 Manager's folder. You can change this - move mp3man32.ini into Windows folder. If you have 2 .INI files (in both MP3 Manager's folder and Windows folder), the one in MP3 Manager's folder is used.