Found this on Worldspawn, cannot find any more infos:
Error: MAX_MAP_BRUSHSIDES
Info:
ERROR: MAX_MAP_BRUSHSIDES [anon.]
Fix:
You have a brush that is too complex. [anon.]
You have too many brush sides (total), in your map. As simple as that. Possible solution, slice up brushes which have sides not visible to use fewer sides. [Kat]
Fix:
This is normally a problem with your total amount of brushes on the map being over the limit, the limit is apparently 32768, so you should try to get rid of some brushes. If your amount of brushes is around that area or you can remove some brush sides, each brush has multiply sides so try removing some of the sides that wouldn't be seen when playing.
Fix:
It means too many TOTAL brush sides in your map. The solution is to reduce the TOTAL number of brush sides (SCDS_reyalP)
EDIT:
[spoiler]Error: MAX_MAPFILE_PLANES
Fix:
Associated with AAS files for Bots or AI. Usually caused by using large numbers of models (with q3map_clipModel in a shader) or large numbers of patch meshes in a map. For Models - removing q3map_clipModel from shader and manually clipping with weaponsclip (or some other clip brush) seems to fix this.
For Patch Meshes - depending on the number of models in a map, converting patch mesh work to ASE models sometimes helps leave clipModel out of shader) to remove the error.
But for AAS problems, ydnar has noted that "BSPC needs to be updated with larger allowable values for planes, brush sides, etc." This affects any Quake3 engine games using Bots or AI. [Kat]
Fix:
You have two choices: cut down on the number of brushes in your map, or don't add bot support. You can try putting clip brushes around heavily detailed brush work, but no guarantees that it will work.[/spoiler]
Try to not clip patches only, Botclip everything complex geometry in your map. Bots hate complex stuff. Or maybe there are to many models?
Are you using BSPC version 2.1h ?
If YES try this version:
EDIT2:
Brushcleanup helped me alot with some problems, if you dont have

try it! /plugins/bobtoolz/Brush Cleanup
But safety first, make a backup of your map. Once you found the problem you can izi-pizi fix it in the original file.
I think you know that, just for sure
