I just installed Updraft on my site (running Wordpress 3.6), filled in my settings and saved my changes. Then I tried to do a backup and the Backup Now button - well, in fact the entire area - is grayed out. You can see what I'm talking in the screen shot I took here: http://www.beliefbb.com/updraft.html
I did install Updraft on another site I have and it worked perfectly. The only difference is that site is running on Wordpress version 3.7.1. Of course the irony is I wanted to do a backup on the first site so I could safely upgrade to 3.7.1.