It seems as if your device is disconnecting in the middle of a transfer.
- What happens if you send 1 book? 10 books?
- Is your device set up to turn off wifi when it sleeps?
- You don't say how many books total you have sent. Is it the 24 you mention, or have you sent books in the past? If the number of books on the device is large (in the thousands) and if the file names are very long (long title, lots of authors) then you could be running into the SD card "maximum entries in a folder" limit. Also note that if/when you are successful in sending all 8,000+ books to the SD card on your tablet you will almost certainly run into the problem described in this FAQ: I have added a lot of books and now adding books takes forever. What do I do?. The solution described in the FAQ solves the "limit" problem as well as the performance problem.
It would help if we could see full debug logs from both calibre and CC. See our FAQ
How do I get help? for instructions. Please erase the multipie.co.uk address when sending the CC debug log.