Arduino Mega

Hi im using this GSM shield in arduino UNO

http://www.elecrow.com/wiki/index.php?title=GPRS/GSM_Shield_v1.0#SoftwareSerial_library_Notes

then the program im using is the SMS _Led Control and its working

but when i used Arduino mega, it doesnt respond like the arduino uno.

whats the problem on the program?

What program?