Thanks Rob, that MS-installer made the trick! 
Overall the new Power Suite v5.49 x64bit seems stable as Rock! 
I have made some fast Tests only. I have tried changing the BANDs-EQ in the “Track Plugin 5 x64 that made seriously crashes before with SONAR x64bit with the old BETA-version. Working all fine now in SONAR 8.5.1 x 64bit!
So far all bugs has disappeared in all plugs in the new v5.49 BETA x64.
I think you should also update all this at the “Main site” that you have added new BETAS.. and why not add that INFO at KVR too!
Perhaps the time is right now to add full support, x64bit versions of POWER-SUITE 5.49?
Best Regards
Freddie