The H8000 has to be in sync with the computer. At the moment, it is running on internal, so unless the computer is synced to it, you will get clicks or distortion.
You could try setting the H8000 to sync to firewire – this should work, but AES or wordclock is better. Or, you could make the H8000 the sync master (set, as it currently is, to internal), but you will have to know how to set up your computer to do this (can't help you with that).
These issues have to be viewed as system design (meaning looking at your setup as a whole) – it is more than just how the H8000 is configured.