"Object of class stdClass could not be converted to int" notice

Hello
Our website Inthessaloniki.com is based on Gossip FX template, joomla 2.5.

In the last 10 days the "Perfect Ajax pop up contact form" is unable to send emails / communicate.

After contacting with the company we received the following message concerning the origin of the issue, that is probably a conflict with open graph and perhaps sd google authorship (?).

""Notice: Object of class stdClass could not be converted to int in /home/inthessa/public_html/libraries/sourcecoast/openGraph.php on line 345. Please contact developer of extension (opengraph from sourcecoast).

Any ideas / suggestions on how to deal with this issue would be of great value.
Thank you for your time!
George