I have found several instances where areas have crashed me
1. The are file is missing - but the area still shows up in toolset.
This was actually some sort of corruption - I found that the area was showing in toolset, but when people tried to go into the area in the game = crash.
The area would also crash toolset when I attempted to open it.
Had to copy the area back into the head revsion of my module, from an earlier version.
2. Certain placeables using the static modifier - those glowing ones - Mythrallar or whatever its called etc
3. Certain tilesets being used on area, but missing on clients
4. If you are on windows - then uppercase / lowercase in filenames/extensions should not cause a problem
Linux however - it is best to have everything as lower case - I think in some instances Windows can accidentally save GIT and GIC files in uppercase.
I use a batch file to rename everything to lower case before I construct my module.
Strictly speaking - the most likely reason for client crash, is a miss match between client and server content.
The server will refuse to start if tilesets are missing on the server installation.
Players will crash when they try to enter areas where they do not have the correct tilesets.
I would recommend you take an inventory of the haks, and override files - if you can get their MD5's too
Then compare between your inventory of your local content.
Are you using differing versions of CEP?
Eg: 2.6 on the server, 2.4 on your game?