[Plugin: Social] Adding accounts link in settings go to 404

I have added facebook and twitter accounts in the profile section.

now I am trying to add the default accounts on the Social > Settings page, but when I hit “Sign in with Facebook” or Twitter I am led to a 404 page not found on my site.

Please let me know how to add the default accounts properly for all admin and author users.
thanks

http://wordpress.org/extend/plugins/social/