Have you downloaded the setup file ?
If so, try copying it to your root of Drive C: then installing from there.
I have come across this before, where the folder paths where too deep, i.e
c:\user\testing my long name\desktop\downloads\filemaker files\new\another long name
The download files will de-compress to their own folder / sub folders making it even deeper and can cause issues.
Loading from the root of drive C: should work