make sure ntrack didn't accidentally create a config file in your song directory - this is a frequent cause of problems. The first time you run ntrack after install, make sure you run the program from its root directory rather than starting off by running from a song file.
If a config-file has allready been written to your song dir, just delete it (and any other strange files or dirs that don't look like they belong - like 'vst plugins'). Then run ntrack from its root dir. Then try opening your song again.