In "An Audience with Lady Nocturnal" the gate won't open when Karliah is supposed to open it.
I've tried pulling on the chain but nothing happens. Is anyone else having this trouble? I try
waiting for an hour but can't open the gate and neither does Karliah.

if you are up to date on your patches this should be fixed on the early version there where a few bugs in this and some ways to fix it like bumping into Karlia when she goes back from the chain if i remember correctelly

Please do not post Spoilers in General.

People come to General to learn about the game without learning about what happens in the game. If they want to know about what happens, that is what the Cheats, Hints and Spoilers section is for.

Do not use quest details or location specific details related to quests/puzzles/NPCs in your posts in this section. General is for discussing gameplay and mechanics. General topics about the the game include but are not limited to races, items and their use, magic, enchanting, skills, character builds, criticism, praise, funny random things that happen, places from an esthetic standpoint and and other general topics.

Use the Spoilers Section if you have to post quest details or other spoilers or a thread about the same. This also includes console commands, and character build exploits.

I will move this now.