Non-static method error – jQuery Vertical Accordion Menu plugin

Hi,
I’ve been using the jQuery Vertical Accordion Menu plugin for quite some time now but when I updated to WordPress 4.1 the plugin throws an error message that looks like the screenshot provided here:

I think I’ve located it to the dcwp_jquery_accordion.php since it doesn’t display the error when those lines are commented out.
What is the correct way to use the add_action?

Thanks!
Best regards
Marcus

function dc_jqaccordion(){
		global $registered_skins;

		if(!is_admin()){

			// Header styles
	//		add_action( 'init', array('dc_jqaccordion', 'header') );

			// Shortcodes
			add_shortcode( 'dcwp-jquery-accordion', 'dcwp_dc_jqaccordion_shortcode' );
		}
	//	add_action( 'wp_footer', array('dc_jqaccordion', 'footer') );

		$registered_skins = array();