Warning and missing footer after migration

Hi,

I recently migrated to a new host provider and ever since I get this message and the footer in http://lovelifesolved.com/newsletter is missing altogether.

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘add_custom_script’ not found or invalid function name in /home/lovelife/public_html/wp-includes/plugin.php on line 503

This is in plugin.php on line 503:

call_user_func_array($the_[‘function’], array_slice($args, 0, (int) $the_[‘accepted_args’]));

The full function:

do {
foreach ( (array) current($wp_filter[$tag]) as $the_ )
if ( !is_null($the_[‘function’]) )
call_user_func_array($the_[‘function’], array_slice($args, 0, (int) $the_[‘accepted_args’]));

} while ( next($wp_filter[$tag]) !== false );

array_pop($wp_current_filter);
}

Please help! :)