The old credit card system was a thorn in my side for years (even after upgrading it) so finally threw in the towel on that. I have migrated us to a Magento hosted credit card gateway. It should resolve intermittent issues that some of the international community experienced with credit card purchases. Accessing the gateway is the same, by clicking the "Support Us" link in the header and following the credit card link. To those having recent credit card payment issues feel free to give this new gateway a try.
Thanks for your patience!