Fatal error: Call to undefined function wp_get_current_user()

I have my site set up as a network… whenever I active this plugin and try to go back into my network I get this error

Fatal error: Call to undefined function wp_get_current_user() in /wp-includes/capabilities.php on line 1287

For now I have tracked it down to the require_once 'settings.php';
in the wp-sugar-free.php file. For now all I am doing is

if(!preg_match('/network/', $_SERVER['REQUEST_URI'])){
	require_once 'settings.php';
}

So that I can use my network area… Anyway just thought id pass this little bug along.

http://ww.wp.xz.cn/plugins/wp-sugar-free/