As known in the SWAT 4 community SWAT 4 TSS game servers are known to crash.
Here are some precautions you may take:
1. In SwatGuiState.ini under [SwatGame.ServerSettings] set: bUseStatTracking=False
2. Block the pepperball gun, there is an exploit around which makes servers crash.
In Swat4XDedicatedServer.ini add under the section [AMMod.AMGameMod]
3. Do not access Chatlog.txt or Swat4DedicatedServer.log through the FTP server when your game server is running, this causes the game server to crash.