Actually anybody that does not have direct line of sight should not be effected, such as those who have a building between themselves and the spell.
I think by the time of Maudrill's turn the whole party is in line of sight of the demon and flaming sphere apart from Zaghigoth.
Maudrill, if you want to take another action, we can retcon. On the same note, it certainly makes for good roleplaying as it is and I can well imagine a spellcaster using a spell for the first time might get unexpected results, especially when using a flaming sphere as the focus for a pyrotechnics spell! As for the demon, you've all certainly taken it down a peg or two, but it still has some fight left in it. Any more spells like stone call that can get around spell resistance?