First of all, apologies for leaving this unanswered for such a long time. I've essentially been offline for quite a while and haven't had a chance to check on Points of Light until recently.
For some reason, it looks like Lulu changed how access to their store works and Points of Light was set to private access only until I was able to log in and accept all the new terms and add the new info required for publishing etc.
It SHOULD be working now.
I just tried again and got the same error a day after:
It has come to our attention that your order CAD-C2411173 cannot be completed because the source files for the project “Points of Light” contain errors preventing it from being printed. We've unfortunately had no choice but to remove this item from your order, and have refunded you accordingly. You should see a refund reflected in your original payment method within the next few business days.
We'll also be contacting the author to make them aware of the problem, but we do apologize for any inconvenience that this may create.