Not a stupid question, but not necessarily one that I can answer, as it involves a number of non-Eventide products beyond my knowledge. Presonus's Web Site is broken, so I can't get any information on their product.
You should check that all FireWire ports on both units are functional – these can be occasionally be damaged by static.
Beyond this, there is no reason I can see why the H8000 should not daisy-chain. I can't speak for Presonus – what do they say ?