Vista - Final Fantasy XI won't download

I purchased FFXI with four expansion packs yesterday for my son and I have been trying since then to install it onto our computer. Our computer is new, purchased in February 2008, it has Windows Vista. With numerous tries, I have been able to install the Playonline Viewer, and Tetra Master. The last install was FFXI and the expansion packs. I have followed all the directions, but it won't download. I have looked online to troubleshoot problem and can not find any help. This is the message I keep getting:

"The install shield wizard has been interrupted and FFXI can not be installed. Your system has not yet been modified."

What needs to be modified and how do you do this?

I hope someone can help us or I have no choice but to return the game.

Thank you.

Hi, Strife523, and welcome to the forums.

Go to Can You RUN It? and make sure that your system is set up correctly to run FFXI.

Not sure if you ever resolved this, but the default PlayOnline Viewer that comes with FFXI is not Vista compatible. I don't know if they ever started packaging the Vista one with FFXI, but if not, you can go to PlayOnline and get the Vista POL here:
FINAL FANTASY XI Official Web Site

This will install, and you can then install the various FFXI packages.