Thanks very much for your help, brf. Unfortunately, I'm still having an issue.
After clearing the forums, New posts were posted. They show up. However, when I view a thread, it's not creating an entry even when the posts were made after I marked the forum as read. In fact, I posted in one and it now shows up as a new thread. Since I was there to make the post and it was made well after I cleared the forums, I would think that it would create an entry in topics_track but it's not.
An example:
my phpbb_users uid has
1352328643
as user_lastmark.
The thread I viewed and posted to has
1352330185
as topic_last_post_time
My user_lastmark is defintely less than the topic_last_post_time, so I would think that an entry would need to be made to the topics_track table when I visit the topic's last page, but it's not. I viewed the topic, posted to it and viewed it again and it's still not creating an entry in topics_track.
What am I missing?