If all was working previously, then a PHP configuration change must have taken place on the server, perhaps by your hosting provider. If so this is probably a config setting so first check the file warpcore/admin/config/config.php.
Open the script file and look for the URI PROTOCOL section and manually set the $config['uri_protocol']
to one of the suggested flavors. I would recommend starting with QUERY_STRING by assigning that variable directly below the flow control statement like:
$config['uri_protocol'] = "AUTO";
if (strpos($_SERVER['SERVER_SOFTWARE'], 'IIS') !== false)
{
$config['uri_protocol'] = "QUERY_STRING";
}
$config['uri_protocol'] = "QUERY_STRING";
If QUERY_STRING doesn't work try sequentially one of the other 5.