Arduino programming on Uno fails using USB download on Windows 2000
Looking at the dump, it says 'Overriding Baud Rate  : 115200'.  look into your /hardware/arduino/boards.txt file, and try changing it to 57600.

from:

uno.upload.speed=115200


to:

uno.upload.speed=57600


I had a similar problem (on ubuntu) with my UNO board and a new Atmega328p-pu chip I ordered. It didn't want to upload.

The Atmega328p-pu datasheet specifies that its transfer rate is 57600 baud, but the  boardx.txt file was set to 115200 baud.  It worked as soon as I set it back to 57600.