>The users of an app of mine are sometimes getting an error 1113 ("File is not open") when an editbox is refreshed. There is no code in the Refresh method, nor is there any code in the parent class. The line number reported is 0 (yes, I have the debugging info compiled in, so it's not that - all other errors generate a line number). Any ideas on this one?

The error may be misleading. Try to see what table is not open, but should be opened in your form (e.g. record aused content in several methods of your form including form's refresh method).