Hello Gordon, my name is Michael. I didn't see a response from you in chat so I switched to the QA format so I could get this information to you.
Just so you understand clearly - we are not afilliated with Corel or the Wordperfect Product. When you provide a rating here, please base it on the accuracy of the information I provide and the level of service I provide to you in communicating the information. If the decsions of these companies were mine to make, many of them would be different.
As you said, Wordperfect X6 requires a version of WordPerfect X4 or higher to qualify for an upgrade of the product. Without an existing version of x4 or x5, the upgrade license isn't valid. Because of that, it won't let you install. Unfortunately, there isn't a legal way to circumvent this since the license itself, to be in effect, requires an accomanying x4 or x5 license. Since your previous version is x2, it doesn't qualify.
However, I do have a suggestion for you that will make the license legally valid and that will make it possible to install. What I suggest is getting the OLD version of Wordperfect Office x4, which is very cheap. Here is an example:Wordperfect Office X4 Standard Upgrade [OLD VERSION]
That will get you to the current version at a much lower cost than buying the full product.
Let me know if you have any questions.