I also found out that in another game, which I play coop with a friend, we didnt face the problem. We removed all 4 bariers by pressing those buttons with right items. I noticed that Wolgraf sees a trap near the entrance of the room with buttons but it doesnt happen during bugged walkthrough. It seems that the floor itself is bugged. Need some kind of patch to fix the floor or to remove these bariers. I remember there was another wierd thing with coop walkthrough - When you first time meet a body of Capitan Nick on a ship. You have to go through lots of traps and explosives and totem that burns you. I did it during my singleplayer walkthrough, but when we came to the place with my friend during coop walkthrough - everything was already destroyed - bombers, totem, mines just like it was when i was playng single. It seems like two diffenrent profiles conflict with each other and it creates certain bugs.