A family of Microsoft relational database management systems designed for ease of use.
First, you should NEVER have to exit out of an app to allow a user to do data entry. That you had to do that indicates your environment is not designed properly. Your app should be split between a back end (the tables) and a front end (everything else). The back end is then stored on a network share while the front end is stored locally on each user's machine. At the least you have a production front end stored on the network.
Then you have a development front end. THAT is where you make all your changes, test them, make sure they work properly and THEN put the new front end into production.
Now to answer your question, did you try doing a compact and repair? Having a single file for an app is an invitation to corruption. The only thing I can tell from that info, is the crash probably occurred running some VBA code. Try the Compact and repair, then split the app and set it up properly.