I picked the ambassador for the dark side, took him to the arbiter's house, and now I am supposed to go to Castle Gloaming and see Archibald. However, I can't seem to figure out how to do that. I enter the Castle fine, but nearly everywhere I go, guards tell me I am not allowed there. One tells me to use the boat, but when I do, a guard tells me I can't go there when I try to get off the boat. What do I need to do?

When you enter Castle Gloaming, walk straight down into the main room and turn left, the guard shouldn't tell you to stop. Jump onto the boat and click the rudder twice, you can now get off and you'll be at the Throne Room.

Thanks. :)