cant upload to duemilanove

I cant upload to the duemilanove anymore, it worked good, but now i get the following error:
’ Binary sketch size: 2556 bytes (of a 30720 byte maximum)
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51 ’
and the chip on the duemilanove is getting hot.
There isn’t anything connected to the board, except the usb which is working properly. The power led is blinking and also the led connected to pin 13.
im using windows 7 64 bit.
I hope you can help me.
Grtz Joost

Check for any blobs of solder or anything that may have falled on the board and be shorting something.

If you have another ATmega chip, try that. Gently ease the old chip out with a knife, each end a bit at a time, so as not to break the pins off.

If you dont have one, you can buy one, but make sure it has the bootloader on it. Sparkfun sell them.