Next Page Bug

I have a page that has a permalink for one of our services. It had a bug where when you clicked on the next page link, it would take you to the next page for all sermons, not just for that service. I ended up changing sb_display_url function in sermon.php by replacing line 405:
$pageid = sb_get_page_id();
with this:
$pageid = $post->ID;

that seemed to fix the problem, but I thought I would post on here in case anybody else is having this problem, and so that hopefully it can get fixed in the next version. Here is a link to the page in case that is helpful:
http://cpcissaquah.org/resources/sunday-school/