We're trying to install the full HP4 on a couple of our servers,
having tested out the imaging and Zen Agent.

When we run the installation program, I can browse to the OU where my
local servers are, and I can see all 5 of them. However, when I select
them, it only lets me install onto one of them, when 4 of them are
running ZfD (one is ZfS only).

What is it looking for to make the determination whether a server is
running ZfD or not? Or is there a know issue with HP4 - I can't see
anything posted about it.