Problem Installing iWork '09 from DVD - Installation Error

For Christmas, I got the box set of Snow Leopard, iWork, and iLife. Everything went smoothly until I tried to open Keynote before class last night to prepare my slides. It was then that it asked for my serial number. When you install from a DVD, you don't need a serial number; it just works. In my case, it wasn't working. I tried a few things with no luck.

Luckily, troubleshooting can be done entirely by researching forums online now--for better or worse is yet to be determined.

I did the typical stuff. My problem is that I had a trial of iWork '09 previously installed. There's some kind of glitch there. It interprets the new install as an online upgrade because if you upgrade online, they email you the serial number.

1. My first attempt at fixing the issue was completely deleting the old programs and their repositories. While it took a REALLY long time, it didn't help.

2. I tried deleting the necessary .plist files but still no luck.

3. I repaired disk permissions within disk utility. This was probably overdue anyway yet didn't help with my iWork issue.

4. Finally, I stumbled upon this forum. I entered "sudo rm -rf /Library/Application Support/iWork '09/" into Terminal and reinstalled iWork using the DVD. I clicked on Keynote and it worked. It simply asked for my registration. I have no idea what I entered into Terminal so if you want to research that more, go ahead. All I know is that it's working now. Thankfully.

Did you have this problem? Did you fix it? What worked?

*Using a MacBook, running Snow Leopard.