Alright, enough. As I said, nanymous made a proactive suggestion, there is really no need for this bickering. The PHP thing has various potential problems down the line (forums updates etc), and I'd prefer to keep things simple.
I think the best thing to do will be to discard the number system, and instead just use usernames as entries. So, you simply post in a competition thread, and if your entry is valid, your name is added to a list. At the end, each name is assigned a number, and numbers are randomely chosen to allocate winners.