This error is not a major error, but it is a pain.
Many Site owners hide the error message:
Warning: array_slice() expects parameter 1 to be array, null given in /home1/wp-content/plugins/zd-header-tags/zd-header-tags.php on line 414
Warning: implode() [function.implode]: Invalid arguments passed in /home1/wp-content/plugins/zd-header-tags/zd-header-tags.php on line 415
I haven’t worked out how to yet.