Database already in use

I am using DT Pro Office My wife (who has a different login on the same computer) and me are sharing a database. This morning I have changed the permissions of this database from “read only” to"read and write", probably when the database was open (which I shoudn’t have).
Now it became impossible for her to open the database at all. She can open other read-only databases, but not this one. DT displays the message “Database already in use!”. Clicking the “ignore” button doesn’t open the database unfortunately.

Please open the .dtBase package in the Finder (via the contextual menu) and then check the permissions of the .database files inside the package. Or if there’s still a .lock file inside the package (and DT is not running), then remove it.