To może wina pliku.htaccess?
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule ^.+,p,([0-9]+)$ index.php\?mode=pos&id=$1 [QSA]
RewriteRule ^.+,c,([0-9]+)$ index.php\?mode=cat&id=$1 [QSA]
RewriteRule ^.+,c,([0-9]+),page,([0-9]+)$ index.php\?mode=cat&id=$1&page=$2 [QSA]
RewriteRule ^.+,c,([0-9]+),order_by,(.+),page,([0-9]+)$ index.php\?mode=cat&id=$1&order_by=$2&page=$3 [QSA]
RewriteRule ^.+,c,([0-9]+),order_by,(.+)$ index.php\?mode=cat&id=$1&order_by=$2 [QSA]
</IfModule>