When I click on 'Map Domain' nothing happens

Please have a look at this forum discussion: https://premium.wpmudev.org/forums/topic/when-i-click-on-map-domain-nothing-happens#post-793401

Please watch this screencast to see what I'm talking about: https://www.dropbox.com/s/rvb3hl9xy6eslge/domain_mapping_not_working.mp4?dl=0

I was asked to send my FTP and Wordpress login details and I've done this several days ago. I've followed every instruction on getting Domain Mapping to work but it just doesn't work. It's extremly crucial to my business to get this to work and the delays in having someone respond to me positively is getting frustrating.

I'm sure if someone can just take a few moments and login this will be resolved quickly.

Please help. I need this to work.