The file you want is MileTracker.settings

I'd do a search on your hard drive to see if there is an older version that has your accounts that you can copy back to the main directory.

This happened to me once and I didn't have an old file and had to rebuild. Argh.

Given the tremendous stability of this program I've learned once a week to use its Backup Settings function and save to a file outside of the program's directory.