wp2bb template code

Hello,

I am creating a new blog whith a new forum.
I need help using wp2bb. I have a pbpbb3 forum and want to link it to my blog.

But, I don’t know what to do whith that :

Place ‘<?php if (function_exists(“wp2bb”)) wp2bb(); ?>’ in your templates

I try to put it in my phpbb template and the blog one but i have again this error.

Fatal error: Cannot redeclare truncate_string() (previously declared in /hermes/web01/b791/moo.**/**/forum/includes/functions_content.php:1124) in /hermes/web01/b791/moo.**/**/wp-content/plugins/wp2bb/wp2bbforum.php on line 333

And this solution http://wordpress.org/support/topic/wp2bb-installation-question doesn’t help me (i don’t have that “comments_popup_link” anywhere).

Please help me to resolve my probleme.

Thank you very much !