I found the bug (I think) but I couldn't begin to tell you what causes it. Tell the Archangel to actually attack the Sathanas and it should fire. I found the same thing though, the main cannon won't fire if the target is directly ahead. I also (finally) found the bug in the big deck guns, so they should fire now as well. Download it again.
originally posted by Spicious
setting the firing point from 0,0,-40 to 0,-8,0 worked for me. I did remove the 80 or so missle turrets which have hull as their parent model
I've changed the down;oad model to that too. The extra turrets are a bug in modview (where I assume you were looking) that is a real pain. Whenever you edit the turrets there is creates the blanks in the missile turret. Removing them in PCS after the fact is perfectly safe if there are any changes that have to be made. Also, if you don't save, those turrets actually aren't in the file to begin with.