Edit: After checking over the [code]s it does not show certain characters that the registry uses, and they show up as question marks where these characters belong, so, I have uploaded and 32-bit and 64-bit registry file for you to edited.
FFXI Reg 32&64 - Mediafire
Use the one that fits your OS architecture.
Modify the paths (mine being D:\\Games\\SquareEnix\\) to reflect your installed location. To do this, extract and open the required reg file for your OS, and open it with notepad. Right-click and hit edit is the easiest way. Hit CTRL+H. Paste D:\\Games\\SquareEnix\\ into "Find what" box, and then type the directory where PlayOnlineViewer, FINAL FANTASY XI, and Tetra Master folders reside into the "Replace with" box. For example, if these three folders are in D:\Stuff\FFXI it would look like this in the replace box. The double \\ is needed for the registry file to understand it's a directory.
http://i114.photobucket.com/albums/n...in/replace.png
When this is done, just hit replace all.
You will notice in the 64-Bit that I have the HKEY_CLASSES_ROOT entries there twice. This is because im not sure where it places them, so I just let it add them twice. Once in hkey_classes_root, and once in the hkey_classes_root\wow6432node directory. Anyway, when you've changed the directories correctly, just hit file -> save, then double click the reg file, hit yes to merge into registry and your good to go.