Just to confirm that your cable wiring matches the connector shown on page 13 of
http://content.vexrobotics.com/docs/...t_20130220.pdf
It can be easy to connect Tx to Tx, etc.
The CAN cabling can be tricky sometimes (more often late at night). Not that this is your issue, but I recall a team at CMP 3 years ago who had only half of their Jags working.. every other one. The team made all cables wrong, but it worked out that two wrongs made it right again.