Base Assault is a mod that requires vehicles and rocket launchers to blow up these vehicles. Stalingrad is quite a small map. I guarantee that anything besides planes added to Stalingrad will cause the server to crash (usually when vehicles run into multiple walls and/or falling off of buildings or ledges).
Without vehicles and bazookas, there's really nothing to add into Stalingrad for Base Assault.
Code:
main: // maps/dm/mohdm6.scr
setcvar "g_obj_alliedtext1" "Stalingrad"
setcvar "g_obj_alliedtext3" ""
setcvar "g_obj_axistext1" ""
setcvar "g_obj_axistext2" ""
setcvar "g_obj_axistext3" ""
setcvar "g_scoreboardpic" "mohdm6"
setcvar "cheats" "0"
setcvar "thereisnomonkey" "0"
setcvar "fraglimit" "0"
setcvar "timelimit" "20"
setcvar "g_inactivespectate" "0"
setcvar "g_gametype" "2"
level waittill prespawn
removeclass TurretGun
//*** Precache Dm Stuff
exec global/DMprecache.scr
level.script = maps/dm/mohdm6.scr
exec global/door_locked.scr::lock
exec global/ambient.scr mohdm6
$world northyaw 270
setcvar "r_fastsky" "0"
$world farplane 150000
$world farplane_color ( 0.6784 0.8353 0.9686 )
exec server_planes/trigger.scr ( -735.70 197.06 -140.31 ) "allies" .2
exec server_planes/trigger.scr ( 1181.32 -263.85 304.13 ) "axis" .2
level waittill spawn
end