Try temporarily disabling your router's firewall, or placing the Roku in a DMZ. See if the error continues to happen. If it does NOT happen, then the issue is likely at the router level.
@RokuShawnS Can you confirm that this bug only affects one lot number that has been suggested in this thread or is this a problem for all 3800's? I don't doubt it will get fixed but it seems to be taking a while, and I don't think Netflix will reimburse us for the downtime.