What method are you using to access the hosted file? Are you using Open Remote? Is the file listed in the Open Remote dialog when you select that server?
This client has a script that connects to the server and initializes stuff... I also have tried the open remote specifying the remote host / database. (Both methods work from other windows 7 computers).
So, I figured this out... in a very obscure forum post on another filemaker forum.
Basically, the installation didn't drop the SSL certs / files for the client... I took them from another client: C:\program files\filemaker\*.pem and dropped them on my windows 8 client... connected just fine right after that.
It's a known issue and why I was asking if you could see the files in the Open Remote dialog.
For More Information see: FMP installer does not install server.pem file
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip