A Minor Problem Buying Software Through App Store

I saw Apple's new App Store on my Mac's dock and wanted to try it. I wanted to buy Angry Birds for $4.99. After clicking the Buy button, App Store kept saying that it could not process my request. I tried doing the same thing three times over two days in case the problem was temporary but I failed every time. Each time, the App Store asked me to review my Apple ID information and I noticed finally that the rule for acceptable password seemed to be different from the last time I created my password. So, I tried logging in my Apple ID account and changed my password to satisfy the new password verification rule. After that, App Store let me buy software with no problem.

So, to summarize, Apple apparently changed their password verification rule so that a valid password created three years ago does not pass the new verification rule (with a new set of letters, numbers, symbols, etc.) and stopped my from using the App Store.