I have an iPod mini. I have used it for years to listen to audiobooks from audible.com. Recently it started having problems transferring files from My Library to the iPod device. It is not a consistent problem - sometimes it will download an audio file and sometimes it won't.

I have reset the default configuration on the iPod several times. I have rebooted several times. I have updated iTunes tot he most current version and rebooted my PC. I have restored the iPod to update the firmware and downloaded a dozen or so audiobook files successfully. I just have problems intermittently.

I don't know what else to try, or how to figure out what the problem is.

I have had only one idea about what the problem might be:
I usually download files in format 3 (audible has 4 file formats called 1 - 4 which correspond to improved sound quality - higher number formats correspond to better sound quality and of course bigger file size; I usually go with format 3 because the sound quality of format 2 isn't great and the file size of format 4 is huge). The files tend to be 40-50 Mb in size. When I can't put a file of format 3 onto the device, I can usually put a file of the same story in format 2 (file size 30-40 Mb) onto the iPod. Is it possible that file size is the problem?

Thanks for any insight you can provide.