This page is intended for people that are using ATI Proprietary Drivers (fglrx) and there's a watermark in the bottom right corner of the screen. The annoying watermark is result of an missing signature key in /etc/ati/signature. It should be installed by default, but by some strange reason, sometimes it isn't. You have to add the signature key by hand, grabbing it from the ati install script. Type in some terminal window:
grep -a signature= amd-driver-installer-<version>.run
It will output the signature key. As root, echo that code, without the "signature=" part to /etc/ati/signature, or just copy it with your favourite text editor.
Restart X, and it should remove that watermark.
If you are trying the beta driver, then you should take the signature from the latest stable release file.