[Plugin: Facebook Social Widgets] Undefined Variable Causing Problems when WP_DEBUG is true

The problem I am having is that while I am developing and have WP_DEBUG set to true I am not able to start a session because the headers have already been sent by the WordPess error handling. Here is the error that I am receiving:

Notice: Undefined property: FacebookWidgets::$pluginDirectory in …/…/wp-content/plugins/facebook-social-widgets/facebook-social-widgets.php on line 26

Warning: session_start() [function.session-start]: Cannot send session cache limiter – headers already sent (output started at …/…/wp-content/plugins/facebook-social-widgets/facebook-social-widgets.php:26) in …/…/wp-content/plugins/wp-custom-admin-bar/custom-admin-bar-functions.php on line 8

My suggestion would be to declare that variable as a member of the class:
protected $pluginDirectory;

Or something like that to get rid of the warning. Thanks for the great work and for helping me out by taking care of this problem.

http://wordpress.org/extend/plugins/facebook-social-widgets/