Cause: Old X1 entries interferring with X2
when installing Sonar on Windows 64, it copies the typical HKEY_LOCAL_MACHINE\SOFTWARE entries to an area that it directs 32 bit applications (a la Program Files x86) to FIRST.
The platinum samples installers are 32 bit so they look at HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Cakewalk Music Software\Session Drummer 3.
So the X2 upgrade updated my Main entry but NOT my mirrored entry.
Once I manually updated these Wow6432Node entries to match, the installer worked like a charm!
P.S. Customer Service at Platinum Samples Rocks!!! Rali's response time was amazing and he had me turn on the logger which once I saw the log file, I knew exactly what was happening.
Thanks Rali!!
P.P.S. Rali didn't even mention he has his own SD3 kits out there. They are friggin awesome too. I'm buying those next. :)