Under Program Files (x86), locate the Square Enix\FFXIV folder. In that folder you'll find your game.ver file. Open the files with notepad, and change the date to that of the most recent update:

2011.04.21.0000


Back the file up on your desktop before doing this. Be sure to hit save before closing the file. If you get an "access denied" error, you may need to copy the file to your desktop first, save it, then stick it back in your FFXIV folder.