Not sure if this is your problem, but in libs/utils.php there is a section of characters you can add and tell it what to convert the character to.
Code:
$output = str_replace("--", "-", $output);
$output = str_replace("/", "", $output);
$output = str_replace("\\", "", $output);
$output = str_replace("'", "", $output);
$output = str_replace(",", "", $output);
$output = str_replace(";", "", $output);
$output = str_replace(":", "", $output);
$output = str_replace(".", "-", $output);
$output = str_replace("?", "", $output);
$output = str_replace("=", "-", $output);
$output = str_replace("+", "", $output);
$output = str_replace("$", "", $output);
$output = str_replace("&", "", $output);
$output = str_replace("!", "", $output);
$output = str_replace(">>", "-", $output);
$output = str_replace(">", "-", $output);
$output = str_replace("<<", "-", $output);
$output = str_replace("<", "-", $output);
$output = str_replace("*", "", $output);
$output = str_replace(")", "", $output);
$output = str_replace("(", "", $output);
$output = str_replace("[", "", $output);
$output = str_replace("]", "", $output);
$output = str_replace("^", "", $output);
$output = str_replace("%", "", $output);
$output = str_replace("»", "-", $output);
$output = str_replace("|", "", $output);
$output = str_replace("#", "", $output);
$output = str_replace("@", "", $output);
$output = str_replace("`", "", $output);
$output = str_replace("”", "", $output);
$output = str_replace("“", "", $output);
$output = str_replace(" - ", "-", $output);
$output = str_replace("_", "-", $output);
$output = str_replace("---", "-", $output);
$output = str_replace("\"", "", $output);
$output = str_replace("--", "-", $output);
May want to give it a try.
Geoserv.