Thanks for using Lunascape! Sorry you're having problems with it.
It sounds like your latest backup might be corrupted. Try to restore your favorites from an older backup, say the second or third to last, and then perform a couple of backups by hand, to create a few uncorrupted backup files.
If you have no older backups, don't try to restore your favorites, but do a couple of manual backups anyway.
Let us know if your problem persists even after you do the above.