Alright so I downloaded the expansion pack: The Sims 3 Movie Stuff and IT IS MISSING the CD Key. So in order to find it i embarked upon a Great Crusade. Here in the following steps is how i fixed this problem and uncovered the CD Key.

*IT IS EASIER IF YOU DRAG THE VIEWING PANE OUT A BIT*

1. Go to your the Start Menu
2. Where it says Search programs and files type in the following: regedit.
3. Click on regedit and look for the following folder titled: HKEY_LOCAL_MACHINE
4. Click on the folder titled: SOFTWARE
5. You'll then need to scroll down to a folder titled: Wow6432Node
6. Scroll down until you find the following folder: Electronic Arts
7. It will then bring a dropdown menu of folders you want the one titled: Sims(Steam)
8. Scroll down to a folder titled: the sims 3 movie stuff
9. Then click on the folder titled: ergc and it should display your CD Key in the upper right.

Or you could search for the following folder:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Electronic Arts\Sims(Steam)\the sims 3 movie stuff\ergc

,but when i tried to search for it, it took a bit longer since the laptop was looking through several files.

Hope that helps you all! PM me if you need anymore help.


{UPDATE: 11/15/2013} You now have access to the CD Key on Steam. They have resolved the issue! Happy Simming :)