Some files and paths on c:\ have no rights for Executing and Writing. Not even for the admin.
But for the installer or apps like SONAR.
A lot of 32-bit-plugins are from ancient times of XP. And are not made for newer systems with complicated file rights.
It would be a nice experiment to place this vst-plugins to an other disc - just for test - where the rights are for anyone.
I don't use 32-bit-plugins.