I have created a database with a form which has a button to bring up a popup form. In an earlier version of the database this worked fine. Now I have made a few changes and I get an error message saying the table (on which the popup is based) is open through the user interface, and cannot be manipulated programatically. The main form contains a subform based on a relational query involving the popup form's table. Could this be the source of the problem, and If so why did it work before and not now?