Alright a few shots in the dark...
Are you playing with a greatly increased number of bots (especially engineers)? My impression from dm_hillb2 testing is that sometimes when there is only one good objective and more than 2 engineers one of them gets bored (zombie).
Are any bots spectating? (did you add more bots than max_players?) in reactor_final I found making a bot spectate resulted in false statements during warmup about having no goals, followed by falsely attributed "kill himself messages" during game play.
Beyond that I am duplicating this from my other post...
LOGS:
Check to see if the files Fritzbot\etserver.log Fritzbot\etconsole.log exist. If so rename or copy them so they won't be erased when you restart ET. There is a small chance these files may help.
This
web page show how to start logging the server and console. Be warned the console gets verbose if you do this,.