iTunes to iPhone "Unknown error 0xE800007F"

I have Wi-Fi Sync active and it works great unplugged from power -- but when I plug my phone into power and it starts syncing, iTunes says the following:

"iTunes could not connect to this iPhone because an unknown error occurred (0xE800007F)."

Searching gives me zilch. Anyone have an ideas? Everything is running the latest verison of iOS, etc., etc...