I’m assuming that you mean the Eye Tracker Browser program (without the “MFC”). Is that right? In that case you are most likely trying to use a Tobii REX eye tracker with the Tobii Analytics SDK, and that won’t work. You should be using the EyeX SDK or possibly the low-level Gaze SDK instead — please see this page for more information about Tobii’s SDK offerings and which SDK to use for what.
I’m sorry for the confusion; in the best of worlds there would only be one SDK (to rule them all!) but we’re not there yet.