Problem in after updating my WordPress to 3.6

I have a web site http://www.astypalaiacamping.gr and after updating to wordpress 3.6 i get this massage.

Notice: wpdb::escape is deprecated since version 3.6! Use wpdb::prepare() or esc_sql() instead. in /var/www/vhosts/astypalaiacamping.gr/httpdocs/wp-includes/functions.php on line 2871 Notice: wpdb::escape is deprecated since version 3.6! Use wpdb::prepare() or esc_sql() instead. in /var/www/vhosts/astypalaiacamping.gr/httpdocs/wp-includes/functions.php on line 2871 Notice: wpdb::escape is deprecated since version 3.6! Use wpdb::prepare() or esc_sql() instead. in /var/www/vhosts/astypalaiacamping.gr/httpdocs/wp-includes/functions.php on line 2871 Notice: wpdb::escape is deprecated since version 3.6! Use wpdb::prepare() or esc_sql() instead. in /var/www/vhosts/astypalaiacamping.gr/httpdocs/wp-includes/functions.php on line 2871 Notice: wpdb::escape is deprecated since version 3.6! Use wpdb::prepare() or esc_sql() instead. in /var/www/vhosts/astypalaiacamping.gr/httpdocs/wp-includes/functions.php on line 2871 Notice: wpdb::escape is deprecated since version 3.6! Use wpdb::prepare() or esc_sql() instead. in /var/www/vhosts/astypalaiacamping.gr/httpdocs/wp-includes/functions.php on line 2871 Notice: wpdb::escape is deprecated since version 3.6! Use wpdb::prepare() or esc_sql() instead. in /var/www/vhosts/astypalaiacamping.gr/httpdocs/wp-includes/functions.php on line 2871

I have disabled the plug ins and changed the theme but the problem is there.

Does anyone know how can I fix it?

Thank you in advance
Armandos