You have to use Smashwords. B&N only takes US for Pubit. Use your file that got through Smashwords. There is a 15% to Smashwords as they distribute your book. It's worth it. For paper books, you use createspace for B&N as well You can link the same ebook and paper book together.
If you have any questions, just ask. Someon will answer.
Good luck and hope to see you in forums.
I'm US and I used a Word 2003 saved as .doc file. It went well.