When I enter Nightcaller Temple during the Waking Nightmare quest, I can't follow Erandur through the wall. Has anyone else had this problem?

It's listed in the bugs section of http://elderscrolls.wikia.com/wiki/Waking_Nightmare

You can use the console command

tcl

(*not* tlc as listed on that page) to pass through the wall. Once on the other side enter the command a second time to turn collision back on.

No, do you use the Unofficial Patches by any chance to fix some of the 'buggier' quests?