If anyone has recently bought one of these drives, or intends to, the following may be of interest. Having plugged in a brand spanking new MyBook Pro 500GB to use as my new backup drive I couldn’t understand why I kept receiving the error “Error Code 0…” when trying to back up files manually (this was before setting it up in Time Machine). I’d even updated the drive firmware and installed the latest button manager software to no avail. Chances are, if you are using one of these drives fresh from the box in OSX, you’ll encounter the same problem if you are trying to back up any large files (especially video files).
The reason is that the MyBook Pro drives are pre-formatted to FAT32 format (to allow Windows systems to use them). However, as FAT32 is a little archaic, it unfortunately cannot handle single files larger than 4GB. As video files are frequently larger than 4GB, the error is easily replicable if you are trying to back up video projects.
The solution: first of all, copy the existing utilities from the My Book drive onto your desktop (or somewhere or your choosing). Then open disc utility (it’s in applications > utilities), select the My Book drive on the left and choose ‘partition’. Select ‘1 partition’ (or however many partitions you want) from the drop down and choose ‘OSX HFS+ Journalled’ from the drop down (the top option). The disc utility will now re-partition the drive and re-format and everything will work fine.

Note: For inexplicable reasons, my My Book drive re-fused to repartition initially to HFS+ format so I had to re-partition first in FAT32, restart and then re-partition as HFS+.