I have a flashing WAIT when launching MYM.

After making a new backup of your broken data as it currently exists, the first thing to try is to replace the little.dbs in the broken dataset (corresponds to the folder name under the root MYM folder -- i.e. CURRENT), with a little.dbs from a recent backup. Usually, this fixes the problem. If not, try installing a new little.dbs file from the original install disks. If this doesn't fix the problem, try replacing the budget.dbs in the broken dataset with one from a recent backup. If that doesn't work, then we need to determine if another file is causing the problem, or your data is corrupted and needs to be fixed manually. Try these steps and let me know how it goes.

What was the last thing you did in MYM that may have caused the error? Did you open two copies of MYM at the same time in Windows? Power outage? Usually, the flashing WAIT is a bad sign and indicates that your data is likely destroyed beyond repair. Hopefully, you have a recent backup to revert to so you won't need to re-enter much data.