Perhaps the easiest way is to let Gerber Omega do it via the installer. From the Main Menu on the installer CD, chose Omega Extras (depending on version, this may be two or three “Menus” deep). The Omega Extras installer will give you the option to perform a complete or custom install. If you chose complete, all extras will attempt to install. Custom will allow you to select only those that you want installed.
If doing a manual install, it is probably easiest to copy the five supplied palette files into the Palettes directory. I think a default install for X3 should have the following path; C:\Program Files\Corel\CorelDRAW Graphics Suite 13\Languages\EN\Custom Data\Palettes. You will find the five cpl files within the CorelDRAW Palettes folder on the installer CD. I think the path for that X:\Setup\OMEGA Extras\program files\GSP\Software\CorelDRAW Palettes (where “X” is your CD drive).