Suggestion to upgrade may not be helpful, but maybe the only choice you have. The Technical Specifications for FM13 does not list Windows XP, which means it is not supported. http://www.filemaker.com/products/filemaker-pro/pro-13-specifications.html
The reason it is not support because something usually doesn't work like it should.
Once we do the Windows upgrade, we'll be running FM13 on it as well. FM13 installer won't run on XP (started with it by mistake)