Hi Thane,
Did you end up using the Gaze SDK or the EyeX SDK? I do not think it would work to have the EyeX Engine and the Tobii Communicator software running simultaneously on the same machine, since they would each assume themselves to be the only software responsible for providing eye-gaze based interaction and also for doing the configuration of the eye tracker (screen setup, calibration, firmware upgrade, and so on).