while uploading sketch the following error messages are shown in the arduino window
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51
i am using atmega8 arduino board
please somebody guide me
This looks very similar to your problem here:
http://arduino.cc/forum/index.php/topic,99081.0.html
Please don't keep reposting in the hope of getting an answer.
And please don't make 'polls'. They are for things like "What is your favourite movie?". Not "I get an error message".