Is anyone using xpresscart (from Merchant expresss) in combination with Authorize.net? Even if not, you may still be able to assist. I get the error message "(99) This transaction cannot be accepted" whenever I hit "make purchase" button on my shopping cart. How do I correct this problem? I have been told the 'fingerprints' don't match, but how the heck to I get them to match?

I am using perl CGI scripts (SimLib.pm, store.cgi, etc). Anyone who is familiar with this error and how to correct it please help. I get the feeling this is a common error that has an easy fix.