[Plugin: Social Connect] login error using any social networks

I have the default install of social connect. I created the app in facebook and put the api and secret in the settings of wp. Everything appears to work except when you login with any of the social networks it looks like it is going to work, but then I get the following error.

Fatal error: Call to undefined function email_exists() in /home1/dgdiamon/public_html/birthdaybirmingham/wp-content/plugins/social-connect/social-connect.php on line 181