require ("inc/config.php");
// Is the script installed?
-if (defined('mxchange_installed') && (mxchange_installed))
+if (defined('mxchange_installed') && (isBooleanConstantAndTrue('mxchange_installed')))
{
// Probe for referral ID
if (!empty($_GET['refid'])) $GLOBALS['refid'] = bigintval($_GET['refid']);