When saving an order with inline credit card payment, this error occurs:

PHP Fatal error: Can't inherit abstract function Netresearch_OPS_Helper_Payment_DirectLink_ RequestInterface::handleAdminPayment() (previously declared abstract in Netresearch_OPS_Helper_Payment_DirectLink_Request) in /magento/app/code/community/Netresearch/OPS/Helper/Payment/DirectLink/Request.php on line 14, referer: http://[shopurl]/checkout/onepage/


This problem can occur when a very old PHP version (older that 5.3.9) is used. It is a bug in PHP, see


PHP needs to be updated to resolve this.

Note that PHP 5.3 has reached its End of Life (see, therefore it is recommended to use PHP 5.4 or higher.