It seems like the card types being sent by the module do not work at Cybersource. The module sends strings like MasterCard, Visa, but they seem to want '001', '002', etc, as per

http://apps.cybersource.com/library/documentation/dev_guides/HOP_UG/html...

When I modified the code around line 135, in ubercart/uc_cybersource/uc_cybersource.module, to use the codes, payments worked. Do you know if this is due to the fact that I'm using a test account? Or has the PHP fallen behind Cybersource's choice of credit card codes?

Thanks!!