Just wanted to add that I’m also getting this error. Would love to see a fix.
…I’m not sure how to go about fixing it myself but this might help some people: If you can live without the scripts and styles boxes on the page\posts creation page then you can do the following to strip it out and bypass the error:
on line 35: in class-sns-admin.php of the plugin files comment out the following code:
add_action( ‘admin_menu’, array( ‘SnS_Admin_Meta_Box’, ‘init’ ) );
…not ideal but works for me; at least the errors gone and i can still add create scripts and css from the admin pages.