The Sims 2 is an old program that causes/d issues for many, I thought I would share my experience of getting past "The Sims 2 Update Error" when installing expansions.
You will need this file, so download it now: http://www.mediafire.com/download/lzbxtj51r6b6e6r/TS2_update.zip
1. Install the Sims 2 normally from disc
2. Copy the files from inside the downloaded zip and folder to "c:\Program Files (x86)\EA GAMES\The Sims 2" and confirm to override the files already there. This will make the program not need to update anymore!
3. Install expansion packs in no particular order
4. Enjoy playing the Sims 2!
Here is the video tutorial: