Receiving "ATError error 3." and "ATError error 16."

Question

I do not know what these errors represent, but I do know that I only receive them when attempting to add some of my e-books (epub) to the iPad through iTunes (latest version as of this moment; 10.6.0.40). To clarify, adding these particular e-books to the iPad (via iTunes) produces  errors on the iPad (within the iBooks application). Specifically, the messages state:
"The operation couldn't be completed. (ATError error 3.)"
After pressing "OK" I sometimes get an additional error: "The operation couldn't be completed. (ATError error 16.)", however this error is a bit more rare, whereas the aforementioned error is ever present.
Another thing to add is the fact that I have successfully transfered other e-books (also epub) without issue. Again, I do not know the significance of these errors, so I am unable to troubleshoot further. Neither Google nor Apple's Support pages have yielded any information of value. Thank you.
P.S. -- When attempting to specify a product (when creating this thread) the iPad 3 (a.k.a., "New iPad") is not available for selection.

Answer 1

Same problem here, but ATError 1 instead. Using iTunes 10.6.1.7 running under Windows 7, 64-bit and an original iPad.
1: Added new ePub generated by InDesign CS5.5 to iTunes. Connect the iPad, check this new book. When the sync completes, I get ATError 1 on the iPad. A bunch of books are now missing from the library.
2: I unchecked the new book and re-synced. Now, one of my older enhanced ePubs from InDesign CS5.5 which opened as recently as last week is the one that can not be written (per itunes). Everything else syncs OK.
3: Unchecked all books in iTunes and re-synced. Samples that I downloaded from iBookStore remain. Everything else goes away.
4. Sync again with only the new book and it opens fine in iBooks. So - the same book that apparently caused the problem in step 1 works fine now.
5. Add back the enhanced ePub from step 2. During the sync, I get iTunes error: Could not copy "title" to the iPad because the file could not be written. On the iPad, I had iBook application open. The cover temporarily appeared in the bookshelf, but disappeared and we get the message "The operation couldn't be completed. (ATError error 1.)" Maybe this book is the problem. I can see the book size is 59,368K. This is large, but not as large as The Beatles Yellow Submarine eBook (317.6MB).
6. I tried adding The Beatles Yellow Submarine back to the iPad, and now *IT* is returning the same error.
In my case, it seems to be a problem with large files, although certainly way under the published 2GB limit. Other (smaller) books with video and audio (including Liz Castro's books) are syncing OK.