Finally got it, That's some poorly written instructions in that config file.
90% of the world when you ask for their url path will put in
http://www.blahblah.com/forums
when all you want is
/forums
I would suggest you add a small comment line with an example that the $url_path, $vb_urlpath, $data_dir are just the directories from your public_html to their location
The "url" in the first two is VERY misleading.