I'm doing the Now or Never quest with Triss. When she's about to enter the room with the rats, she stops in the doorway. I can't get past her. She won't move, I can't talk to her, and nothing seems to draw her away. It's a total dead end.

Help.

This happens a lot.
Save your game & when you reload, she will be a bit further forward

I did this. It didn't work. Saved in all sorts of places. Standing right behind her, back a couple of rooms, in the middle of the prior room. Nothing helps. She just stands in the doorway staring into the next room. And she only says, "Well?" if I try and talk to her. It's maddening.

It worked for me a couple of times, you'll just have to go back to an earlier save & make sure you get through the door before she blocks it.
Because she always stops there.

I just found this:

Geenmachine:
"Step 1: Summon Roach
Step 2: Get Roach into the house. Yea odd I know but if you get him to the door and confuse him then he will path toward you when it wears off.
Step 3: Get roach next to our Mage Tress, of the order of the infinate wallrun. Face him towrard our lovely companion and dismount.
Step 4: Confuse both Roach. Hopefully Roach will roam forward and push her past the point where pathfinding is clipping with the wall / railing or whatever and get Ms. Sorenoggin Wallrunintoin fixed. I had to do this from some distance away as it seems that you have a certain near distance that you can not use signs if friendly NPCs are the target. Thankfully the confuse sign is longer range than this bounding area."

Source: http://steamcommunity.com/app/292030/discussions/0/613958868364331762/

I know that you have a different situation but perhabs this will help you. Good luck!

Same sort of thing happened in Skyrim,until they put a mod out.So it's
gonna have to be fixed in a patch.

Have you tried Aard?

Yeah, none of the spells work on her.

I finaly just went to a save about 10 minutes back

Yeah - I also did not find any solution, other than load the save from an few minutes back (luckily I save often), and than run in front of her trough that gate. If you let her go first she get stuck.