I've read this book and thought it was RUBBISH!!! I have a paper copy and, like you, bought it coz it mentioned a Basenji. The story was a quite poor but what really got me was the lack of proof reading that had been done. There are spelling mistakes, words missing, wrong words etc etc the whole way through the book.
However, all of my Bs wag their tails, albeit not exactly the same as a Labrador may but their tails definitely wag from side to side and round like a helicopter
Have you read Goodbye My Lady?
http://www.zandebasenjis.com/books.htm This is a good link to B related books.