I *think* it's a windows issue... the folder is probably not really created below Program Files. It's only made visible there for users and programs, but creating folders in the program-folders directory is normally forbidden, except for elevated setup-programs.
Windows more or less allowed the creation, but these folders are created in the users virtual space.
I think Win64 bit version simply does not allow it anymore.
To see if 64 bit Forcedirectories work, try to create a folder manually (in Explorer) like C:\test
Then grant proper rights to this folder.
Now try if 64 bits lazarus prog can create folders inside this c:\test
fwiw ;-)
John