Problem loading audio books

I purchased a reconditioned M230 from Woot and it came without any CD or instructions.  I downloaded the instruction manual but it said nothing about loading audio books.  I hooked the M230 up to my computer and copied an MP3 into the ‘Record’ folder on the M230 and it played without problems.  I then deleted the MP3 and coppied an Auto Book (aa file) to the Record folder but the M230 still says that I have no files on the unit.  Can anyone help me out here?  Woot said this unit would play audio books, were they wrong?

Audible content can be located under the “Spoken Word” category of your device.  Scroll past the music selection and you should find it.