Access 97 Shared Database Locking Errors

I have developed an Access 97 Database that 5 of my coworkers share. They are all entered as users with full permissions with myself as Admin.
Frequently, when more than one person is using the database, and they go to close, he/she gets an error that will not let them close out. The error says something to the effect of “Couldn’t lock/save…currently in use by user [insert user name here] on computer [insert computer name here].” I have taken off all record locking options, but still get this error.