I apologize in advance for suggesting something really lame for the
problem. We struggled with the same thing (using LabView) and it turned out our laptop switched to a different WiFi hotspot following the re-image, or somewhere along the way.
i.e. we were connected to the cRIO with the imaging tool, started the Format process, stuck on Rebooting cRIO for a very long time. Turned out we were now connected to the School's WiFi instead of the robot WiFi.
(this sort of thing often happens when robot power is cycled, taking down the D-Link too. I can't explain why it happened in this case).
If you are stuck there again, check that you can ping the robot:
cmd> ping 10.xx.yy.2
or see if you can get to the dlink
cmd> pint 10.xx.yy.1