Not sure if you are still figuring this out, but I solved it and documented it on another thread.
Had the same problems, now it is working! Here’s what I did:
1. Choose the “Use Facebook admin” button.
2. The page returns a 404! Oh noes 🙁
3. Change the URL (remove the bolded part of your URL):
from this: http://url.com/wp-admin/admin.php?page=wpseo_social&key=SECRETNUMBERSOHMY&userid=0000&userrealname=My%20Name&link=http://www.facebook.com/w00tw00t#_=_
to this: http://url.com/wp-admin/admin.php?page=wpseo_social&key=SECRETNUMBERSOHMY&userid=0000&userrealname=My%20Name
4. Party time! Now add the URL to the Facebook insight dashboard, the meta tag is now live.
Throw a response if it still isn’t working. 🙂
