error on search page

Hi, i get this error on top of the search page:

Warning: Illegal string offset ‘preset’ in /home/xxxxxxxx/public_html/wp-content/plugins/wp-custom-fields-search/wp-custom-fields-search.php on line 387

i m using PHP 5.4.17 and mysql 5.5.32 and the latest version of the plugin.

http://wordpress.org/extend/plugins/wp-custom-fields-search/