repeat for each....

[Mark Smith]

This is driving me barmy...can any kind soul here explain why this 
works:

on tryLoopWith
   put "a,b,c,d,e,f" into charList
   repeat with n = 1 to the number of items in charList
     put item n of charList into line n of newCharList
   end repeat
   put newCharList && "with"
end tryLoopWith

but this throws up a 'bad chunk expression" :

on tryLoopFor
   put "a,b,c,d,e,f" into charList
   repeat for each item n in charList
     put item n of charList into line n of newCharList
   end repeat
   put newCharList && "for"
end tryLoopFor

I haven't yet been able to make the 'repeat for each...' structure work 
at all, not even once, in any circumstance, in a year of trying it from 
time to time. I can find nothing in the electronic docs to help me. I 
am mystified.

TIA,  Mark Smith