groovetube,
FYI...there is no commenting box for Joomlaboard. Basically, when you enabled Joomlaboard comment function you allowed your users to click the link, "Discuss this article on the forums. (0 posts)."
Which means, when someone click on that link they're able to reply to that blog entry into the Joomlaboard.
In order to do that you need to set the, "Joomlaboard Forum ID for comments" in your mamblog configuration menu.
It should be located at the bottom of the 'Settings' tab of Mamblog configuration menu.
I hope this help. Good luck!