Thanks for verifying this one, it wasn't so trivial after all.
About the query, all I can say is that I tested it out quite a lot in phpmyadmin and the results looked right. But this wasn't working before - the "min_correlations parameter" was too low (actually, I think you found that out) - and now it's too late to change the database structure to make this more efficient (I tend to really dislike comma-separated fields in something that should be a relational database...).
This should now be working.