[nathanww]

If you're doing a "cold" boot of the robot, there's a condition where the DS/cRIO link may not work(Essentially the bridge doesn't boot fast enough to pick up the cRio's announcement that it is online, and as a result, refuses to relay messages to the cRio because it doesn't think anything is connected).

Rebooting your Classmate will solve the problem, because it will cause the classmate to ask the cRio to re-send its announcement. However, a quicker way to accomplish the same thing is to reset the cRio without powering down the bridge. The bridge will then be able to discover the cRio and connect it to the DS.