Downloading audio books from audible to muvo v100 mp3?

I have a 2gb muvo v100 player. i want to download audio books on it. i went to audible.com and downloaded 3 books. then tried to transfer it to my mp3 player. athis message popped up. muvo does not take format 4 on it it accepts formats 2 and 3. i have tried transfering it [...] http://bit.ly/pmM1pr