Getting error message every time I update or attempt to preview

I am getting this error message every time I try to make an update to my pages:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘_category_transient_flusher’ not found or invalid function name in /home2/imneeto/public_html/wp-includes/plugin.php on line 470

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘_category_transient_flusher’ not found or invalid function name in /home2/imneeto/public_html/wp-includes/plugin.php on line 470

Warning: Cannot modify header information – headers already sent by (output started at /home2/imneeto/public_html/wp-includes/plugin.php:470) in /home2/imneeto/public_html/wp-admin/post.php on line 235

Warning: Cannot modify header information – headers already sent by (output started at /home2/imneeto/public_html/wp-includes/plugin.php:470) in /home2/imneeto/public_html/wp-includes/pluggable.php on line 1121

I have tried to re-install but it still there so maybe is something I have done or am doing that has caused this. On my other WP site this issue does not exsist.,