Call to undefined method stdClass

Hey!

I’m having some issues with your plugin.
When I enable the plugin and then enable it one one of my posts the site will throw me an error like this:

PHP Fatal error: Call to undefined method stdClass::have_posts() in C:\www\sota\wp-content\plugins\bbpress\includes\replies\template-tags.php on line 201

What can I do to mend this?

Thanks in advance!

http://ww.wp.xz.cn/extend/plugins/bbpress-post-topics/