still having problems with Nim. using python 2.6.4

I have attached the file that the game is on. feel free to modify it to make it better. all suggestions are welcome. if you don't want to download the file then here's the code:

Nim game being created, no GUI used... Need tips...

I am creating a game called Nim, but cannot get a loop going no matter what I do. What i am trying to do is get it to only accept input from 1 to 4, and keep asking for input from the same player if he/she enters in an invalid number. I also want it to stop when there is 1 or no piece(s) left,