Thanks for the reply. I checked to make sure I have the correct version of Data Assist (I didn't have a previous version of Form Builder). I deleted the Dreamweaver Cache file and reset the space layout but I'm still getting an error message when I click "Edit Form": Error Initializing Add Form UI: TypeError: DWfile.getAttributes(orig) has no properties.
Then I get the error from my initial post when I click Finish and it tries to update the form. It works fine as long as I don't save it as a preset, but I need to be able to get back in and change it without redesigning the form again.