[Dr. Drib]

I had a SOMEWHAT similiar problem with my Kindle once: Calibre showed the file loaded, but it wasn't at all visible on the Kindle.

I then did this, which solved the problem:

I deleted the file from my Kindle and then safely unhooked my Kindle. I let about 1 minute go by and then hooked the Kindle back to my computer with calibre already loaded. I then added the file back to the Kindle. This time, before unhooking the Kindle, I waited until the Kindle showed it had disconnected itself from my computer, before I physically removed the USB cable.

This solved the problem. The only thing I can think of is that I too quickly disconnected the Kindle from the computer.