Can ping RoboRIO, but can't connect

[cjl2625]

On one of our roborios, I've successfully reimaged, and updated the firmware on all the components of the control system.
(On our other roborio, it just refused to reimage altogether; that's another story. Though despite refusing to reimage, I can at least connect to it in the driver station)

I've tried connecting through the robot radio, ethernet, and USB.
In the driver station, the diagnostics light on the robot is always green, and when connecting wirelessly, the robot radio light is also green.
In the page where you select the team number, clicking the arrow menu shows 2067-frc as a detected roborio.
I've uninstalled antivirus and disabled all firewalls.
I've tried connecting on three different computers, and restarting the driver station and the robot repeatedly.
From lurking the forums, I've tried various solutions, but I can never get a successful connection.

I've spent hours these past few days trying to resolve this, but our control system seems completely dysfunctional.

Any ideas?