Re: *seamless* wordpress integration
That is a very clear error message: the system cannot find the file you are trying to include in bbPress. You started the file path with /blog. which is an absolute path, starting at the root /. You will probably have more luck with this:
require_once( '/home1/endingho/public_html/blog/wp-blog-header.php' );
The $bb->WP_BB = true; part I am unfamiliar with. But the error is indicating that you have the path wrong.