1. The UUID must contain only alphanumerical characters, the period (.), the at symbol (@), the underscore (_), and the dash (-). Unicode characters are not allowed. Try matching your UUID against this regular expression:
$ python Python 2.7.2 (default, Jul 8 2011, 18:54:13) [GCC 4.6.1 20110627 (Red Hat 4.6.1-1)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import re >>> re.match('[-a-zA-Z0-9@._]+$', 'firstname.lastname@example.org')
2. Your extension must not end with gnome.org. Extensions are not affiliated with GNOME and must not appear to be.