Warning: call_user_func_array()

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'mytitle' not found or invalid function name in /var/www/inline/data/еее/wp-includes/plugin.php

$content = get_post_meta($post->ID, 'title', true);
function my_title()
{
global $key;
global $content;
return str_replace("%key%",$key,$content);
}


function mycontent($content)
{
global $key;
return str_replace("%key%",$key,$content);
}

add_filter('the_content','mycontent');
add_filter('the_title','myh1');
add_filter('wp_title','my_title');