I believe you can extract the forms files. I would extract them to the desktop and then open the xsf with notepad. I am not sure how much you know about what needs to be in xsf files or xml but I would caution to tread carefully. If you want you could post this file up here and I might be able to resolve the issue. But once you fix the xsf you would then repackage the files back to an xsn file.