Hmm...xpolsys, it seems no one has tested your version - if they did they would have already complained...lol..
You see, here is your script:
;Artificial Intelligence Script
;Header
desc = Plr Save In Zone
;Triggers
:state=0:hudreset,hudx=50,hudy=50,hudimagefine=gamecore\text\autosave.tga,hudname=autosave,hudhide=1,hudmake=display,state=10
:state=0,plrwithinzone=1:quicksavegame,state=1,hudshow=autosave,hudfadeout=autosave
;uncomment next line to save each time plr enters zone
;state=1,plrwithinzone=0:state=0
On your new state=0, it goes to state=10. But there is no state10. So, you need to make the second state=0 (the save part) state=10.
So, here's the quick fix:
;Artificial Intelligence Script
;Header
desc = Plr Save In Zone
;Triggers
:state=0:hudreset,hudx=50,hudy=50,hudimagefine=gamecore\text\autosave.tga,hudname=autosave,hudhide=1,hudmake=display,state=10
:state=10,plrwithinzone=1:quicksavegame,state=1,hudshow=autosave,hudfadeout=autosave
;uncomment next line to save each time plr enters zone
;state=1,plrwithinzone=0:state=0