Uninstall it and reinstall it. I know with the PC (I play on console) there was an older version of the launcher that needed to be uninstalled and you needed to re-install the new one. That error is what many get when they don't have the latest one installed. I can't remember the details.. let me find you a link.

http://ffxiv.zam.com/forum.html?foru...129469640&h=50

Here are some other articles that may help:

http://www.gamefaqs.com/boards/96061...nline/62619263
http://forum.square-enix.com/ffxiv/t...-version-check