hmmmm I'm a bit stumped here, I have to admit . . .
The brown out fuses were programmed in before being shipped, which should have prevented any corruption.
What is your programmer type? MKII? Also, try hitting the erase button a few times and see what happens . . .
With the Mote power on, when you plug in the ISP connector, does it look like the Mote resets? (normally, it's supposed to reset, and will interfere with your LED flashing for a second or so)