I don't know what to do.   Dimension Pro will not show up as a VST in Sonar X3 regardless of what I do.   Are that many products not compatible with Windows 8.1 or AMD Radeon's varients of desktops.    Is there a fix for this?

Dimension Pro is a separate installer. Assuming you installed the synth, does the stand alone version run? If so, run it as administrator to register. Once registered, it should show up as a VST after scanning. If it fails to show up, run a VST reset http://www.cakewalk.com/S...ommended-for-Upgraders

You failed to mention which version of Sonar X3 you're installing.
 
Only Sonar X3 Producer Edition comes with Dimension Pro.
http://www.cakewalk.com/Documentation?product=SONAR%20X3&language=3&help=Plug-ins.1.html
 

Sonarx3 E

The Stand alone version does run. but neither the 32 or 64 vst will

OK I got it to show up but it will not accept my registration code.  I have tried cutand paste and I have copied it down and hand-entered it which it didn't like that either.  It doesn't like the registration code any idea why?

Close out of SONAR, then reopen by right-clicking and choose Run As Administrator, then insert Dimension Pro and enter the registration code.

Yup do as above.  It's a weird quirk of Dim Pro and Rapture tot complete the  registration process, they want/need to be  launched with Run As Administrator, and it's just the way it is for those.
 
That does only apply to the completion of the registration code authorization process, so you can run normally without having to do the Run As Administrator thing though, once you finish registration.
 
Bob Bone