Part of the problem is that there were no updates past 10.4.11. So I'm not sure where you downloaded those updates, but they're most likely some kind of trojan. Probably just as well you haven't been able to run them. And odds are the reason is that they're x86 executables and you have a PPC.

In any case, the most often source for the spinning beachball I run across as an Apple repair tech (just not working for Apple) is a failing HDD. So if this problem is getting more and more frequent, and seems to be particularly bad when you open a program, then you probably want to be in the market for a new HDD. Laptop or desktop, odds are very good you're talking IDE/PATA drives. So, might want to buy one while they can still be found. They're getting ever harder to find every day.