you can not install this product . because another version is already installed ......
How are you trying to install X8? From the original disk? Or from an installer file?
Some of the older installers (e.g., as were on the original disks) can now produce that error.
You should make sure that you have the "newest" version of the X8 installer. You could try getting one here: Get your CorelDRAW software here!