If you don't have problems with those two, however, I fail to see what is stopping you from winning the encounter. I've done it at least 10 times now, and with silence + marilith I have a 100% win rate
I'm probably just bad at the game. The queen just casts other spells that kill my dudes if I use Silence. Silence just keeps her from using her highest level spells. One of the spiders that shows up with her also casts accelerated spell on itself and its buddy. The queen casts accelerated spell on herself and they just have their way with my party. Between the three of them, they use 5 spells/powers that do tons of damage.
The queen doesn't even move out of the silence. She just sits in it like, "You think this is gonna stop me?" I even tried putting a wall of energy or Prismatic Wall on the floor to try to make her at least use her move action to move instead of using two spells, but she didn't mind standing in it.
I just gotta get those three spiders in the second wave before they get more than one spell off.
Just to be clear, I haven't been sitting here trying this non-stop. I load up the game maybe 0-2 times a day and give it another shot. I think I can get it, but it's another example of Pierre taking what would be a decent encounter (the first batch of spiders), then adding a scoop of "fuck you" with the queen and her two friends. Just when you think, "wow, I barely survived that," another fucking caster shows up with high level spells and a bodyguard that's immune to most things for that double "fuck you" goodness.