Bug with mobs (Quake 4)

The situation is,so I downloaded quake 4 and here's the problem,starting with the very first mission where you need to bring a medic he gets near the stairs and stupidly in circles around her and does not go further. With this problem I figured out how to take care of that and pulled him to the stairs and while he was stuck in a few places on the next laps I brought him, and then the fun begins,Konda meet with the squad badger for Stripping and destroying air bases, the situation is repeated,but that does not matter I some how pushed to the gate that would be opened but on the second gate they stupidly run after you and don't open them well, here I nohow solutions in the form of cheat code walk through walls that would have closed doors to pass and move on but it's full of horror,the game loses all sense of plot by the fact that the story revolve and what does not. Maybe someone knows how to solve this problem?(this problem with almost every unit in the game,even in cosmoe truck before reaching the first extraction point is stupid because of the fact that men run circles around him