iRobot release version 2.0.0-34 of the Roomba firmware, which changed the network protocol used to communicate with the robot. As a result, the plugin is unusable until the new protocol is reverse engineered.
Progress is being made on this (not by me), and as soon as a working implementation is available, I will update the plugin. If you're interested in following progress on this, go to https://github.com/koalazak/dorita980/issues/10