[Paul M]

Well the error means that its trying to subtract 6 from a value that is actually less than 6 to start with.

I'd be a lot more worried about what that code is actually doing, it looks like its running updates on user records for every post in a thread, so if your thread has 4000 posts, thats 4000 updates !

In fact, since its running one query to get all the postids, and then looping round them using fetch_postinfo(), its quite likely most of the posts dont exist in the postcache, so its also running individual queries to get each post, potentially another 4000. :erm: