I Looked at the old thread Need Help Deleting Legacy Registry keys W7 64 bit
you originally followed to try and fix LEGACY permissions in the registry.
The info in that thread is above my skill level, so i can't give you any advice what to do to change/fix permissions.
It does help explain what you tried and why...and that's good to know.
Hopefully installing Ver 1.61 will fix your issue.
If you still have problems deleting the LEGACY registry keys, someone more skilled than me will need to help you. Brink, Dwarf, and Bill2
posted in the old thread and probably can help with this.
Also, as you have the MBAM Pro version, you should be entitled to (free) Malwarebytes Support.
I believe they would be able to help straighten this out.
I also suggest learning and using Backup Imaging for your OS and programs.
It's the best way to backout/recover from problems like this...
YUP, your retail CD is at best a drink coaster