Wordpress Open Social Error:"Strict Standards: Only variables should be passed by reference"

I am using the Open Social Plugin in Wordpress. I also installed the Debug Plugin to see what is going on. I get a PHP Error saying:

Strict Standards: Only variables should be passed by reference in /wp-content/plugins/open-social/open-social.php on line 111.

Line 111 in open-social.php:

'google'=>"http://ift.tt/1IwJpbJ".(isset($_SESSION['WPLANG_LOCALE'])?$_SESSION['WPLANG_LOCALE']:'en_US')."&sl=zh-CN&tl=".(isset($_SESSION['WPLANG_LOCALE'])?reset(str_split($_SESSION['WPLANG_LOCALE'],2)):'en')."&u=%URL%"

Does anyone know what is wrong with this line? I am stuck here.