Ok, this is the problem. You can only put 64-bit applications in system32 folder, but Screensaver Factory screensavers are 32-bit applications for better compatibility with a wider range of computers. For some reason Microsoft has made it confusing like this and we can't do anything about it. The system32 equivalent for 32-bit screensavers is c:\windows\SysWOW64 folder, but I would suggest just installing them to either windows or Program Files folder to avoid these problems altogether.
Blumentals Software Programmer