[Q] Help using a latin american cel with an Airtel SIM topic

Hi there,

My girlfriend went to India this season, and take her cellphone with her, it's a samsung GT-S5660L (bought in Chile)
a friend there borrowed her an Airtel sim card, but when she put it on the phone, it asks for a pin code
(already tried 1234 and 0000)
don't know what else to do, any advices?