Map Loading Problems & Solutions
 
Successfully compiled my .qle file and got the .bsp file. But when I try to run my level by loading another multiplayer level and type into the console "map [mapname]" this message  

"PF_setmodel: NULL"  

is shown. 

PFSETMOD.ZIP by James Battles (note: this is directed at Worldcraft users but may prove helpful nonetheless) 
 
When starting Quake2 with a custom bsp file, the following message is shown at the console:

ERROR: CMod_LoadBrushModel:
\maps\mymap.bsp has bad version number(2524 should be 38)

The solution or explanation goes here.
I believe I have put to much of something in my map. It is a fairly large Quake2 map with about 75 monsters and a LOT of light. The error is 

"error:*index: overflow"

This happens when I try to start the map in Quake2. The only thing that changed from when it worked to when it did not work is a few more monsters and perhaps one carve. 

I believe you are correct. The QuakeLab2 masthead (that big picture up top) generated this error - a BFG was fired in a room full of all the Quake2 monsters. I think it has to do with the game having to deal with too many entities. Try dropping most of your light entities, and replacing it all with texture based lighting (edit those surface properties!) Try and avoid putting too many monsters in a given scene, as this will cause the framerate to crash and burn, and in extreme cases, might help generate this error.
Your QBSP problem goes here. The solution or explanation goes here.
Your QBSP problem goes here. The solution or explanation goes here.
 
 and on and on...