Hi @Vladislav and @Jack Kitterhing
I made a plugin with the code posted by @tia_williams and it worked http://pastebin.com/ufRwkkBy . But I need improve the steps occur when the "terms and conditions" are not accepted. This are the steps in my site:
1. press facebook register button http://postimg.org/image/87vbxs5xz/
2. load facebook profile (and not select the "terms and conditions" by error http://postimg.org/image/3wm2mc14x/
3. go to a register OK page confirmation?!!! http://postimg.org/image/8dqdel1h3/
4. come back to a facebook load profile to see an icon "loading" http://postimg.org/image/kg2kjstgv/
5. finally go to my register error page http://postimg.org/image/p15xnia4h/
I need something more simpler when somebody forget check the "terms and conditions" checkbox. This can be do?