[hack346]

try this

open your backend/functions.php

find this line

function searchfield($s) {
    return preg_replace(array('/[^a-z0-9]/si', '/^\s*/s', '/\s*$/s', '/\s+/s'), array(" ", "", "", " "), $s);
}

replace with:

function searchfield($s) {
    return preg_replace(array('/[^a-zA-Zа-яА-Я0-9]/si', '/^\s*/s', '/\s*$/s', '/\s+/s'), array(" ", "", "", " "), $s);
}