It's all PHP and MySQL-based, but obviously with a lot of HTML/Javascript and CSS chucked in, Ian.
I'll be honest, I think it would be hard for anyone else to "do" much with the Pairs Ladder page, as it's several thousand lines of fairly convoluted and un-commented code. Part of the problem is that I wrote the code in the first place, but even I will need to spend several hours just going through it all to re-acquaint myself with how it's structured, let alone finding the things that need amending in the code to get the whole page working like clockwork again. It was working fine before, so it may even be a question of the Ladder settings data being out-of-kilter.
It'll be a lot of trial and error to track down exactly what is causing the problems in the first place. I need to clear 2 whole days completely, because it's really not something you can successfully tackle a bit at a time (at least, I can't).
The Teams Series and Teams Ladder pages are similar. Most of the IAC website is fairly simple (assuming you're into PHP) once you understand how the W3 css works, but those are the three most complex pages on the whole site. It's not a question of your skills as a programmer, which I don't doubt, but it's mostly a question of understanding how my mind works and how I've structured the code.