Hi,
I just got an arduino fio, and I had some different sketches running on it (just for some practice). Until I made a typo in one of my pinMode settings, writing 1, OUTPUT instead of 10. After upholding this sketch I haven't been able to communicate with the arduino, I assume it is because the Rx pin is now configured as an output. I don't know how to reset the memory in the board, it has a button but it doesn't appear to be doing anything.
Try holding down the reset pin when you start your sketch download, don't release it until the IDE says "downloading xxxx bytes of 32768" or similar.
That way your sketch is not starting, the bootloader will start first and the comm's with the PC will have a chance to start.