VRAD hates me - FinalLightFace Crash

Unfortunately, VRAD hates me. Since Hammer got updated, it occasionally crashed when it came to "FinalLightFace" when compiling. I didn't think much of it and sorted it out remaking some brushes.

For my new map, all was going well until I get the same error again. I've removed some props, detail brushes etc via VisGroups with some success. But I still don't understand why it keeps crashing with some relatively normal brushes and props. What I am basically asking is,
a) Why does this happen and what is causing it?
and
b) How do I prevent this from happening in the future;Here's a compile log of when I have got it working

** Executing...
** Command: "c:\program files\valve\steam\steamapps\psychofreak001\sourcesdk\bin\vbsp.exe"
** Parameters: -game "c:\program files\valve\steam\steamapps\psychofreak001\counter-strike source\cstrike" "C:\Program Files\Valve\Steam\SteamApps\psychofreak001\sourcesdk_content\cstrike\mapsrc\cs_swords"

Valve Software - vbsp.exe (Jan 2 2006)
1 threads
materialPath: c:\program files\valve\steam\steamapps\psychofreak001\counter-strike source\cstrike\materials
Loading C:\Program Files\Valve\Steam\SteamApps\psychofreak001\sourcesdk_content\cstrike\mapsrc\cs_swords.vmf
Can't find surfaceprop stone for material DE_TIDES/TIDES_BRICK_WALL_D, using default
Can't find surfaceprop stone for material STONE/INFBASEB, using default
Can't find surfaceprop concret for material DE_TIDES/TIDES_WALL_01, using default
Can't find surfaceprop stone for material DE_TIDES/TIDES_BRICK_WALL_G, using default
Can't find surfaceprop stone for material DE_TIDES/TIDES_BRICK_WALL_I, using default
Can't find surfaceprop stone for material STONE/INFFLRA, using default
Can't find surfaceprop stone for material STONE/TIDSTAIRSATP, using default
fixing up env_cubemap materials on brush sides...
ProcessBlock_Thread: 0...1...2...3...4...5...6...7...8...9...10 (0)
ProcessBlock_Thread: 0...1...2...3...4...5...6...7...8...9...10 (1)
Processing areas...done (0)
Building Faces...done (0)
Chop Details...done (0)
Find Visible Detail Sides...
Merged 14 detail faces...done (0)
Merging details...done (0)
FixTjuncs...
PruneNodes...
WriteBSP...
done (0)
writing C:\Program Files\Valve\Steam\SteamApps\psychofreak001\sourcesdk_content\cstrike\mapsrc\cs_swords.prt...done (0)
Creating default cubemaps for env_cubemap using skybox materials:
skybox/tides*.vmt
Run buildcubemaps in the engine to get the correct cube maps.

No such variable "$hdrbasetexture" for material "skybox/tidesrt"
Can't load skybox file skybox/tides to build the default cubemap!
Finding displacement neighbors...
Finding lightmap sample positions...
Displacement Alpha : 0...1...2...3...4...5...6...7...8...9...10
Building Physics collision data...
done (0) (364547 bytes)
Emitting linux collision data (use -nolinuxdata to disable).
Building Physics collision data...
done (1) (795199 bytes)
Placing detail props : 0...1...2...3...4...5...6...7...8...9...Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
Material NATURE/BLENDMILGROUND004_2 uses unknown detail object type militia_sand_grass!
10
Water found with no water_lod_control entity, creating a default one.
Compacting texture/material tables...
Reduced 1156 texinfos to 871
Reduced 63 texdatas to 57 (1477 bytes to 1260)
Writing C:\Program Files\Valve\Steam\SteamApps\psychofreak001\sourcesdk_content\cstrike\mapsrc\cs_swords.bsp
3 seconds elapsed
Memory leak: mempool blocks left in memory: 3

** Executing...
** Command: "c:\program files\valve\steam\steamapps\psychofreak001\sourcesdk\bin\vvis.exe"
** Parameters: -game "c:\program files\valve\steam\steamapps\psychofreak001\counter-strike source\cstrike" -fast "C:\Program Files\Valve\Steam\SteamApps\psychofreak001\sourcesdk_content\cstrike\mapsrc\cs_swords"

Valve Software - vvis.exe (Jan 2 2006)
fastvis = true
1 threads
reading c:\program files\valve\steam\steamapps\psychofreak001\sourcesdk_content\cstrike\mapsrc\cs_swords.bsp
reading c:\program files\valve\steam\steamapps\psychofreak001\sourcesdk_content\cstrike\mapsrc\cs_swords.prt
972 portalclusters
3668 numportals
BasePortalVis: 0...1...2...3...4...5...6...7...8...9...10 (11)
Optimized: 25720 visible clusters (0.00%)
Total clusters visible: 813366
Average clusters visible: 836
Building PAS...
Average clusters audible: 960
visdatasize:241645 compressed from 248832
writing c:\program files\valve\steam\steamapps\psychofreak001\sourcesdk_content\cstrike\mapsrc\cs_swords.bsp
11 seconds elapsed

** Executing...
** Command: "c:\program files\valve\steam\steamapps\psychofreak001\sourcesdk\bin\vrad.exe"
** Parameters: -game "c:\program files\valve\steam\steamapps\psychofreak001\counter-strike source\cstrike" "C:\Program Files\Valve\Steam\SteamApps\psychofreak001\sourcesdk_content\cstrike\mapsrc\cs_swords"

Valve Software - vrad.exe SSE (Jan 16 2006)
----- Radiosity Simulator ----
1 threads
[Reading texlights from 'lights.rad']
[1 texlights parsed from 'lights.rad']

Loading c:\program files\valve\steam\steamapps\psychofreak001\sourcesdk_content\cstrike\mapsrc\cs_swords.bsp
2505 faces
1 degenerate faces
329444 square feet [47439940.00 square inches]
22 displacements
9168 square feet [1320207.88 square inches]
2504 patches before subdivision
18398 patches after subdivision
2 direct lights
BuildFacelights: 0...1...2...3...4...5...6...7...8...9...10 (49)
BuildVisLeafs: 0...1...2...3...4...5...6...7...8...9...10 (30)
transfers 1729163, max 876
transfer lists: 13.2 megs
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (1)
Bounce #1 added RGB(51275, 29559, 18392)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #2 added RGB(9503, 2617, 1070)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #3 added RGB(2418, 266, 86)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #4 added RGB(775, 29, 8)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #5 added RGB(300, 3, 1)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (1)
Bounce #6 added RGB(131, 0, 0)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #7 added RGB(61, 0, 0)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #8 added RGB(31, 0, 0)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #9 added RGB(16, 0, 0)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #10 added RGB(9, 0, 0)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #11 added RGB(5, 0, 0)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (1)
Bounce #12 added RGB(3, 0, 0)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #13 added RGB(2, 0, 0)
GatherLight: 0...1...2...3...4...5...6...7...8...9...10 (0)
Bounce #14 added RGB(1, 0, 0)
Build Patch/Sample Hash Table(s).....Done<0.0160 sec>
FinalLightFace: 0...1...2...3...4...5...6...7...8...9...10 (1)
FinalLightFace Done
Ready to Finish
0 of 0 (0% of) surface lights went in leaf ambient cubes.
ComputePerLeafAmbientLighting: 0...1...2...3...4...5...6...7...8...9...10

Object names Objects/Maxobjs Memory / Maxmem Fullness
------------ --------------- --------------- --------
models 1/1024 48/49152 ( 0.1%)
brushes 509/8192 6108/98304 ( 6.2%)
brushsides 3837/65536 30696/524288 ( 5.9%)
planes 2448/65536 48960/1310720 ( 3.7%)
vertexes 5933/65536 71196/786432 ( 9.1%)
nodes 1751/65536 56032/2097152 ( 2.7%)
texinfos 871/12288 62712/884736 ( 7.1%)
texdata 57/2048 1824/65536 ( 2.8%)
dispinfos 22/0 3872/0 ( 0.0%)
disp_verts 1782/0 35640/0 ( 0.0%)
disp_tris 2816/0 5632/0 ( 0.0%)
disp_lmsamples 11852/0 11852/0 ( 0.0%)
faces 2505/65536 140280/3670016 ( 3.8%)
origfaces 1622/65536 90832/3670016 ( 2.5%)
leaves 1753/65536 56096/2097152 ( 2.7%)
leaffaces 2962/65536 5924/131072 ( 4.5%)
leafbrushes 1236/65536 2472/131072 ( 1.9%)
areas 2/256 16/2048 ( 0.8%)
surfedges 18229/512000 72916/2048000 ( 3.6%)
edges 10578/256000 42312/1024000 ( 4.1%)
LDR worldlights 2/8192 176/720896 ( 0.0%)
HDR worldlights 0/8192 0/720896 ( 0.0%)
waterstrips 205/32768 2050/327680 ( 0.6%)
waterverts 0/65536 0/786432 ( 0.0%)
waterindices 3291/65536 6582/131072

I know one reaso that's causing it: Any piece of non-right-angled, complicate brush architecture. I once had an arch which I skewed in a way I thought it was still in grid but after I did I got the same crash you're getting.

Maybe try to look at all the brushes you added last like a CSI dude, searching for some more unusual connections and intersections, anything that's even slightly off-grid. You can also use cordon compile for parts of your map and see in which the compiler crashes.

I got it working fine without deleting it now =/

I just copyed and pasted it into a new file and it compile perfectly fine :S

Thanks for your help anyway.