try this
flash file download from same link
Welcome to the ./downloads/Karbonn/A6/ folder of the support area for your service center
flash with Celkon A85 Flash tool
here the link for Flash tool & Software Procedure
Flash tool - Download - 4shared - Cheerala Srinivas
open tool and
flash with karbonn A6 firmware
and follow the instructions
i think u r problem will be solved