I hate to ask the obvious but you do have antennas attached to both the revo and oplink? I know it sounds stupid to ask but it has happened
I just did an upgrade and erase on both a revo and an oplink to wipe all their settings.
To get them to connect I plugged in the oplink with the revo powered down, set the power to 25mw, left the baud rate at the default 38400, checked coordinator, clicked save at the bottom of the page, gave it a minute to make sure the settings were saved, unplugged the oplink, gave linux (I'm on a linux box) a minute to disconnect and the oplink config screen went away. Plugged in the oplink again, went to the oplink config page, verified the settings were still there, wrote down it's device ID, and unplugged the oplink again.
I plugged in the revo, went to the oplink config page, set the power to 25mw, left the baud rate at the default 38400, filled in the coordinator ID with the 8 digit device ID from the oplink, made sure coordinator wasn't checked, clicked save at the bottom, gave it a minute, and unplugged the revo.
I then plugged the oplink back into the computer and powered up the revo with a battery. After a minute or so everything connected.
edit: another thing, when you switched to LibrePilot did you do a firmware "upgrade" or an "upgrade & erase"? If you don't do the erase it doesn't always work right.