bbpress only works with the TwentyTen child theme that compes with the wordpress bbpress plugin. So unless you modify the theme yourself, I don't understand why it would have worked offline as oppose to online - it just shouldn't have worked at all! Bbpress using the default theming of bbpress if a child theme isn't activated.
There is a TwentyEleven theme for bbpress available on someone elses blog but I'm currently having problems with it myself, so I recommend sticking with the TwentyTen for now. Note that there is a plan to theme TwentyEleven in the next release of bbpress: http://bbpress.trac.wordpress.org/ticket/1518