For those still struggling with the garbled forums page in a stock woothemes canvas installation (or child theme off canvas) this support post at WooThemes really helps:
http://support.woothemes.com/entries/24051302-Fix-bbPress-forum-search-in-Canvas
The woo team created a simple bbpress template for use in canvas and included the attached files – one template file and a some code for functions.php.
Works like a charm.
