Problem checkout with book

I have a problem about checkout... I need prevent a user from editing a node that is already being edited,
and the other user need be informed that node is being edited. I see this work, but not for me, maybe it is another problem:

I installed checkout, and I´m using in a node type book, and when the user check out the node, only
this user can edit, but others users don´t receive msg "This document is being edited by...", and can´t edit.
This is bad becouse others users don´t know what is happening.

Other thing, the type book is a hierarchy, and the nodes below isn´t
checked out, and only user that checked out the above can edit, the others can´t. The page is redirect to main page.

Thanks for any help.