The errors are
attacks2.dm:22:error:givePL:undefined var
attacks2.dm:23:error:givePL:undefined var
attacks2.dm:9:error:cookie:undefined var
attacks2.dm:9:error:givePL :duplicate definition
attacks2.dm:12:error:givePL :previous definition
attacks2.dm:9:error:= :expected a constant expression
attacks2.dm:22:error:usr/:/maxPL:undefined var
and On Lines below i have
Lines 22
usr:maxPL += abs(givePL)
Line 23
usr << "That cookie gave you [num2text(givePL,30)] PL! Yum!"
Line 9
var/givePL = cookie
Line 12
var/givePL = 0 //var to hold how much PL the eater gets
The usr:maxPL error is probably caused by maxPL being defined for all mobs. Try using . instead of : and it should clear up.
On line 9 and line 12 you've defined givePL. Now I'm guessing what has happened is you've got something like this:
Now what's wrong here is badCookie already has a givePL var, so you don't need to define it again. You just need to override the default setting.
So the following would work (appart from that error with cookie we discussed before):