Launcher update problems - My Solution
So I had the update error. I can't post a step by step with screens because I've already solved my issue for today's update. It goes something like this. Navigate to your boot folder before attempting to launch the game.
You'll find it at X:\whatever\SquareEnix\FINAL FANTASY XIV - A Realm Reborn\boot
http://i2.photobucket.com/albums/y34/defade/ffboot.jpg
Select the file ffxivboot.exe
Launch the game. At the point when the progress bar freezes on the update and it seems to be doing nothing, go ahead and manually delete the file I mentioned above. The updater will then write the new updated file.
In case the updater also fails in the same way when updating ffxivlauncher.exe then try the same process.
It seems the updater doesn't get the correct permissions to overwrite those files. Running admin mode or taking full ownership of the files didn't work for me, but this method did. I hope it works for you!
edit: Be sure you're running them as admin to be on the safe side.
edit2: Here is the ZIP of my boot folder in case you have no luck with the method above.
http://rapidshare.com/files/39197318...Sep%202013.zip