Q&A plugin errors in debug mode

Hi

In debug mode on my wordpress v3.8 site the Q&A plugin is throwing up the below errors. Please could you let me know if it's an incompatibility between the new version of wordpress or if there's a conflict with custom code:

Deprecated: Function split() is deprecated in /Applications/MAMP/htdocs/green_kartel/wp-content/plugins/qa/core/edit.php on line 180

Notice: Undefined property: stdClass::$site_name in /Applications/MAMP/htdocs/green_kartel/wp-content/plugins/qa/core/subscriptions.php on line 88

Warning: Cannot modify header information - headers already sent by (output started at /Applications/MAMP/htdocs/green_kartel/wp-content/plugins/qa/core/edit.php:180) in /Applications/MAMP/htdocs/green_kartel/wp-includes/pluggable.php on line 896

It is also showing the following error in the WP backend (image attached):

Notice: bp_setup_current_user was called incorrectly. The current user is being initialized without using $wp->init(). Please see Debugging in WordPress for more information. (This message was added in version 1.7.) in /Applications/MAMP/htdocs/green_kartel/wp-includes/functions.php on line 3049

Thanks for your help