Try disabling the iTrainz chat interface - Start Trainz (to the screen where you get Tutorials, Routes etc) , and go to <Main Menu> then <Options> then <Global Interface Addons> and uncheck the iTrainz interface.
Also check out the Trainz Internet Connection settings - these are in <Options> (from the Launch menu - not the same "Options" as above!!) <Planet Auran> tab.