Ahh...I was also wondering why my ad-aware wouldn't update.
Do I have to pay to get the ad-watch it installed on my computer. It says that I need plus or pro, but did anyone download that without having to pay and was still able to use it?
No, you can still get Ad-Aware free. All the Plus or Pro editions do is put a real-time monitor (called Ad-Watch) thats supposed to actively help keep spyware out, rather than wait for you to run a scan.
IMO, you'll be fine with Ad-Aware 2007 free edition. Just make sure you run it every now and then.