Problem:

Customer had spent a long time developing a screenset, and one day received an error which indicated that the screenset was corrupt in some way.

Resolution:

If a screenset gets unexpected corruption of any sort, then it is always worth trying to salvage it by exporting the entire screenset as a .imp file (which is really just a text file).

Check the file for any obvious funnies (half-lines, mistyping, or if you know that a particular object is the one causing the trouble, delete all references to it). Then create a new screenset, and delete the only window (select it and press <Delete>).

Import the .imp file into the screenset, and say 'OK' when informed that some duplicate global dialog will be renamed. You should then have a more or less working screenset. If you have removed any objects from the .imp file, try adding them to the screenset again.