If you see this error:
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51
Give Da_Hero's solution a try. After several days of hair pulling frustration I saw his post and gave it a try it worked like a charm!!
His solution is in this thread:http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1187909552;start=all
If it works for you please spread the word so others don't have to suffer through this for as long as we all have. Post something in this and other forums so others don't miss the solution.