The card is a Visa Electron or pre-paid Visa Debit card.  Blackbaud Merchant Service (BBMS) supports processing through Visa, MasterCard, Discover, American Express, and Maestro (for deposits in Euros only).  Visa Electron cards work similarly to a Debit card, but require that all funds be available at the time of charge.  Although a facet of Visa, Visa Electron cards are processed using a different merchant identification mechanism that is not supported by Blackbaud Merchant Service.  Many pre-paid Visa Debit or Gift Cards also use a different merchant identification mechanism not supported by BBMS.  To resolve this issue, ask the constituent for a different form of payment.