[Plugin: NextGEN Gallery] Won’t let me add new posts

When I go to add a new post I get the following error:

Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'searchnggallerytags' was given in URL/wp-includes/plugin.php on line 166

Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'searchnggallerytags' was given in URL/wp-includes/plugin.php on line 166

Warning: Cannot modify header information - headers already sent by (output started at URL/wp-includes/plugin.php:166) in URL/wp-includes/classes.php on line 1571

It’s only since upgrading both WP and NGG, however it displays fine on the pages where the gallery is, and the backend of the plugin works fine too. It just displays this code whenever a new post is submitted. It doesn’t actually stop me submitting a post either, it’s there once I get past the error message. Anyone got any ideas?