inspire7

Hi, I've just added the header tags seo to my site, and I found I've got a warning in the admin section: Warning: call_user_func() expects parameter 1 to be a valid callback, function 'header_tags_reset_cache' not found or invalid function name in C:\wamp\www\catalog\admin\includes\functions\general.php on line 1193 And I think this is why my products when selected in the catalog get a message saying webpage cannot be found. Would anyone know what the warning is about and how I can fix it?