Ah ok, if your english isnt very well, its ok .
I think i understod your problem. THe only strange thing is, i cant reproduce it.
Thats very anoying. What i do when enetering a side or ceiling door is:
Climb up(side door), open it, climp higher(so feets are above the uper corner of the opened door) and than i enter(with ducking of course).

When i get stuck inside a closed door for example, its always possible to open it. And sometimes the engine itselfs pushes me out.

Maybe you could do me a favour and record a video?

WHOHOO :D, got your problem(at the side doors). I think what you do is:
Climbing up the ladder,opening the door, "jumping" onto the opened door, moving at least one step forward without ducking(here i got stuck in front of the door inside the wall). If you go a similar problem at the ceiling, its still strange(not yet reproduced) but now iam on the problem with the side doors.


GReets
Rackscha