Its rather usual to find errors in books. I have yet to come across any book that has no mistakes/typos. Don't be discouraged, it shows that you're reading carefully & most importantly, you know your stuffs.
So instead of getting disappointed/angry/discouraged with errors that you found in the book, post it here & share it with us. There're a couple more of free resources such as the API & EJB specifications that you could use together with the HFEJB for your preparations.