EDIT: Solved: I just needed to open SONAR as 'Administrator'
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When I open Dimension Pro it asks for a serial number and registration code. "Invalid registration code".  The serial number is pre-filled correctly and I copy and pasted the registration code that corresponds to this SN from my Cakewalk account.
I even tried the lost registration tool and it gives me the same registration code that doesn't work.  
Any ideas?
 

Open DimPro as a stand alone using Run As Administrator, that should do the trick.  
Never mind...I see you figured it out...