The appropriate windows were tested on the test server (all of last week), as well as the live servers today.
I loaded it on three different accounts (on separate hard drives). I have not heard of anyone else having this problem (and believe me, I would have lol).
Make sure that you do not have any spaces in your folder name (ex: Sparxx UI)
Try creating a new folder (with no spaces in the name), download a new copy of the UI and try again.
Post here if that does not work.
(Edit)
If when you do a /loadskin in-game, and do not see your Sparxx folder name in the list, there has to be something wrong on your end filewise:
Here is the link to EQInterface.com's FAQ on how to install a UI:
http://www.eqinterface.com/forums/f...q_howto_install