First patch for KmQuake4 in Quake 2 that solves the error of map number 9 "annex to the aqueducts" so that the vehicle does not get stuck and can move forward.
To install just replace the pak0.pak file in the quake 4 folder and you're good to go. You can now pass the mission and reach the tunnels in the center of the nexus. Only applicable for the KmQuake 2 version.