crash when build lighting

[bagit_reds]

dear all,

i have a big problem, after i modified geometry, i want to build without lightmass (because it can take a long time)
but something happened
first, geometry build did well, path build also got no problem at all, but when lighting build started to "build static lighting", seconds later my UDK went crash and have to quit

oke, i have to do it again, when i opened my file and tried to build, it crashed agan i've tried over and over but still got the same problem and same problem

so i tried to build lighting with lightmass, when the swarm agent appeared, the process stop, and it said "failed to build, read log"
but i didn't understand at all what the log was trying to say

help me please

[bagit_reds]

help me please

[bagit_reds]

help again

[xxmiggixx]

If you want to youse lightmass u need lightmass importance volume. Reinstall that helped me.