[Alan Anderson]

The cRIO's Ethernet port is deactivated briefly a couple of times during the reimaging process. Some computers take longer than others to recognize when the connection is back, and the reimaging software times out if it takes too long. That might be what you're seeing.

Or it might not be, since you mention having tried it with a router in the middle, which usually keeps the problem from happening. Whatever was going on, I'm glad you found a way around it.