I had the same problem, and talked to support. This is what he told me to do, and it worked!
Run an extension cord from the bottom receptacle of the outletlinc (the one that is always on) to the PLM that is connected to the ISY (yeah, I ran it from the bedroom all the way to the basement where my router, modem, and ISY are).
Go to the Administrative Console and Link Management and Start Linking.
I guess it was too far to establish a link, but close enough to work once linked.
Good luck!