Not sure if this has been posted, but the errors you may be receiving is due to an issue with the third party that is taking payments for SE. This is assuming it is a third party. Even if it isn't, the following link is to an excel spreadsheet that details the different error codes during the payment process.
https://www.usaepay.com/console/supp...ors/errors.csv
Obviously, you may be wary of clicking on it and I understand, but since it is safe, I went ahead and grabbed the two errors it could be. (401/601)
401 Selected bank is not available The SVP Bank ID that was specified was not found in the list of valid financial institutions for selected merchants
601 Invalid card reference token The cardnumber field appears to be a card reference token but the token does not exist (this could be the CVV or it could be a token generated from your credit card number. This is a common practice for PCI compliance)
11000 Is a generic gateway error when communicating with the payment server
I know this info from being in a financial support position with the technical side of an ERP solution for a company. We also use 'tokens' from a specialized third party so that we do not have to cover the cost to upgrade and maintain PCI compliance in order to hold credit card numbers of our customers.