Taken from The QuakeLab: Editing website
http://www.planetquake.com/quakelab/
Used by kind permission of Steve Fukuda

                               [The QuakeLab]
              [Compiling and Editing Problems and Solutions]

            [Editor] [BSP]  [Light] [VIS]  [Startup] [Gameplay]

                            Modified June 7, 1997
|-----------------------------|-----------------------------------------------|
|Problem                      |Solution                                       |
|-----------------------------|-----------------------------------------------|
|                             |If a map with a large amount of brushes was    |
|                             |compiled with standard QBSP, LIGHT may do      |
|                             |this. Workaround: Recompile the map with       |
|                             |QBSP256B (see Tools section in The Basics)     |
|                             |and re-light. - Shawn Holmes                   |
|                             |-----------------------------------------------|
|Light caused invalid page    |Works under Windows 3.1, strangely enough.     |
|fault in module at           |Possibly an incompatible motherboard (?) -     |
|0000:3b646177 (this value is |Nicholas Lawson                                |
|always the same)             |-----------------------------------------------|
|                             |This solution applies to both your averge      |
|Registers:                   |pf, and the qbsp256's tendency to cause a pf   |
|EAX=00000009 CS=.......      |instead of displaying an error message when    |
|EIP=.... etc. etc.           |handling csg or portals, (at least it does     |
|                             |this to me - anyone else?)                     |
|Bytes at CS:EIP:             |                                               |
|                             |First: are you running                         |
|Stack dump:                  |3dsstudio/netscape/adobe photoshop/psp etc.    |
|675c3a64 .... etc. etc.      |in the background at the same time your        |
|                             |trying to compile your level? Close all open   |
|Message displayed when LIGHT |programs then restart your DOS prompt box      |
|crashes after a few          |and try again. If this doesn't work then       |
|completely normal executions |restart the computer, to clean up memory.      |
|of the program. Hardware     |                                               |
|fault? WIN95 problem?        |If this doesn't work, then move a              |
|                             |brush/brushes in your level a bit, (1 or 2     |
|                             |squares) or just offset part of your           |
|                             |geometry a bit. This usually fixes it if the   |
|                             |above two things don't work, I have no idea    |
|                             |why slight changes in the level fix this       |
|                             |sometimes but hey it works! - George Davison   |
|-----------------------------|-----------------------------------------------|
|                             |Basically, it means just what it says. There   |
|                             |is apparently a limit to how many different    |
|                             |lights can be reflected off of one surface.    |
|                             |There are two ways to induce this problem:     |
|                             |a) too many lights in one room, or b)having    |
|                             |many holes or portals which can allow light    |
|                             |from other areas to come in and affect a       |
|                             |surface.                                       |
|                             |                                               |
|                             |I don't know what this limit is...maybe an     |
|                             |email to John Carmack mights straighten it     |
|                             |out.                                           |
|                             |                                               |
|                             |I would try to reduce the number of lights     |
|I'm starting on a level and  |in any given room, until it compiles. Or, if   |
|just started adding lights   |it was induced by many holes in walls or       |
|to the two rooms I have so   |ceilings, minimize those. - Mike Melzer        |
|far. Most of the lights will |-----------------------------------------------|
|be spotlights (i.e.,         |There are a maximum of four light styles       |
|targetted), but a few are    |incident on a single surface. All normal       |
|"normal" lights. After       |lights are the same style, so you can have     |
|adding about a dozen         |fifty little lights in the same room and it    |
|spotlights and three normal  |won't hurt.                                    |
|lights, I got this message   |                                               |
|from Light:                  |Each type of flickering light is a seperate    |
|                             |style. Each targetname present on a light      |
|WARNING: too many light      |(controlled by a switch or trigger) is a       |
|styles on a face             |separate style. This is likely where the       |
|                             |problems occur. - John Carmack's response to   |
|I'm assuming this means that |Mike Melzer                                    |
|the face of some brushes are |-----------------------------------------------|
|being illuminated by both a  |The source of the light was a "normal" light   |
|spotlight and a normal       |entity with brightness of 300; the target      |
|light. The question is: why  |was a "normal" light entity with a             |
|is this bad? - Robin         |brightness of 0. Changing the target to a      |
|Hermance-Moore               |path_corner got rid of the warning.            |
|                             |                                               |
|                             |Note: It turns out that in Worldcraft, a       |
|                             |brightness of 0 does NOT mean "cast no         |
|                             |light". What it means is "use the current      |
|                             |value of the map's default light level         |
|                             |variable". As currently implemented, that      |
|                             |light remains at the original brightness       |
|                             |given to it, regardless of what the default    |
|                             |light level is changed to. This is             |
|                             |confusing, since it makes it possible to       |
|                             |create a light for which you can not           |
|                             |determine the brightness (looking at the       |
|                             |properties still tells you "0"). - Robin       |
|                             |Hermance-Moore                                 |
|-----------------------------|-----------------------------------------------|
|----- LightFaces ----        |                                               |
|323 entities read            |                                               |
|************ ERROR           |And the corresponding solution is...           |
|************                 |                                               |
|GetFileSpace: overrun        |                                               |
|-----------------------------|-----------------------------------------------|