Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:18.104.22.168) Gecko/20101203 Firefox/3.6.13
steps to reproduce:
1. Notice the "I accept this Agreement" button in https://addons.allizom.org/z/en-US/developers/addon/submit/1
"I accept this Agreement" button is disabled and user is blocked from proceeding with the upload.
verified fixed @ https://addons.allizom.org/z/en-US/developers/addon/submit/1