For the Windoze booting issue, here are a few things to look at:
1. Are the correct & current USB drivers for your motherboard installed? Update the drivers to the most current.
2. Are the correct drivers for the BU303 installed? I know the BU353 uses the Prolific USB-to-serial drivers. I don't know about the BU303.
3. Do you have USB boot enabled in the BIOS?
As far as MapMonkey being free, it is. The Destinator maps that are used are NOT free, however.
Although at this point it's somewhat of a grey area. Destinator no longer exists as a company. I don't know how that affects their map data and rights to it.