They have 32- and 64-bit versions for Windows, but only 64-bit for Linux.
Although there is a link for fah_control for 32-bit Linux, that is only the control program. You also need the fah_client program. They no longer have one for 32-bit Linux.
There is also a viewer program called fah_viewer. However, when you run that it doesn't show the actual protein your client is processing, it only shows demos. That's probably because their servers are overloaded. They posted they were having some problems because they have had a 20x increase in people running the programs, so they need to increase server capacity, etc.