verification error

Hello,

I believe I have a problem similiar to this one:

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1215617395/0#0

In short, the arduino continues to run the last sketch uploaded but will not load new ones, I get:

avrdude: verification error, first mismatch at byte 0x0000
0x39 != 0x00
avrdude: verification error; content mismatch

Is there anyway to recover this without an avr programmer to reload?

Thanks.