I guess you have tried all this - but just in case:
It may be that Win uses another directory, for instance this: C:\Users\Hans\eTeks\Sweet Home 3D\furniture
Did you try Help-About-Libraries? Clicking an existing library (if any) should tell you which directory to use.
Assuming you have taken the libraries out of the .zip container so you have .sh3f files, did you try double-clicking them (provided file associations work) OR Furniture-Import Furniture Library?
As for what you are doing wrong, one possible conclusion could be "using Win 10"
ok
