Hi Mike,
does the CAN Demo Box transmit CAN frames at the baudrate that the CAN
Receive.vi example uses? By default, both use 125k, but that default
value might have been changed.
Further more, you can (manually) disable all transmission of the CAN
Demo Box. Navigate to the 'CAN Transmit' option on the CAN Demo Box
(using the 'Menu Select' button) and make sure that it is not set to
'Disable All'.
Also make sure that you connect that port of the
8461 card to CAN Demo Box that the CAN Receive.vi example runs on.
Does any of this help?
-B2k