hi all im attempting to update coryApp script and im getting the following error

PHP Warning: Division by zero

can anyone help on this please be much appreicated heres is where the error is coming from

if(isset($error) && !empty($error))
            echo '<p style="margin:0px; padding:5px 20px"><font color="#FF0000"><small><i>'.$error.'</i></small></font></p>';
        $config['showeachside'] = 4;
        $config['per_page'] = 20;
        $config['js_numrows_page'] = mysqli_num_rows(getListState($str, ''));
        $config['curpage'] = empty($_GET['p'])?1:$_GET['p'];
        $config['rs_start'] = ($config['curpage']*$config['per_page'])-$config['per_page'];
        if($config['js_numrows_page'] < $config['per_page'])
            $config['per_page'] = $config['js_numrows_page'];
        $page = (isset($_GET['p']) && intval($_GET['p'])>0)?'&p='.$_GET['p']:'';
        $config['cururl'] = $base_url.'admincp/states.php'.$pstr;
        $rs_maxpage = ceil($config['js_numrows_page']/$config['per_page']);
        $paging = Pagination($config);
        $list = getListState($str, " limit ".$config['rs_start'].", ".$config['per_page']);
        if(mysqli_num_rows($list)>0){

and here is the function for it

if(!function_exists('getListState')){
    function getListState($str='', $limit=''){
        global $conn;
        $sql = "SELECT StateID as Id, State as L1Value, s.CountryID as L3Value, Country as L4Value from ".$GLOBALS['table_prefix']."states as s inner join ".$GLOBALS['table_prefix']."countries as c on c.CountryID = s.CountryID ".$str." order by StateID desc ".$limit;
        $query = mysqli_query($conn,$sql);
        if(!$query)
            return '';
        else return $query;
        }
    }

anytime your getListState returns an empty set $config['per_page'] will be 0

okies would i have to change this

from

if(mysqli_num_rows($list)>0){

to

if(mysqli_num_rows($list)>100){

as i have read in google but still brings same error

output all your variables at different points to see whats in them