How to Repair files / or instal new expansion
if you just installed a new expansion or had to repair files again to fix your game,
(first instal the game or the new expansion)
do this steps exactly:
1. Download the following file: http://uploading.com/6f69ddmf/PXI-FFXI-UpdatePatch-zip
2. Extract its contents to your c:\program files\PlayOnline\Squareenix\Final Fantasy XI.
3. Run PlayOnline
4. Select Check Files on the left of the screen.
5. Click on PlayOnline Viewer then select Final Fantasy XI from the drop down, then Check Files.
6. After some time of updating, FFXI should be up to date.
7. Exit PlayOnline Viewer.
8. Copy the data folder at C:\Program Files\PlayOnline\SquareEnix\PlayOnlineViewer\data to the Final Fantasy XI directory at C:\Program Files\PlayOnline \SquareEnix\FINAL FANTASY XI.
9. Afterwards you should have the directory C:\Program Files\PlayOnline\SquareEnix\FINAL FANTASY XI\data.
start the game with the client you want and your game wil work again.