trouble with GPS shield

am using the adafruit GPS shield and when i tried download any gps code to the dem.. 168 arduino board i get this warning
Binary sketch size =6462
avrdude:stk500_getsync(): not in sync:resp=0x00
avrdure:stk500_disable():protocol error ,expect=0x14,resp=0x51
I am new to arduino so pls. help
also I ran the LCD display program and it worked fine