Step 1. back up the file  "WantsTuning.package" located in the folder listed below:

"C:\Program Files\Ea Games\The Sims 2 Pets\TSData\Res\Wants"

Step 2. Place the file "WantsTuning.package" in the folder listed above.

Step 3. Place the file "Woohoo.package" in  the folder "My Documents\EA Games\The Sims 2\Downloads"

*** Very Important make sure you back up the file listed in step 1 you will need to restore that file before installing any new patches,addons or expansion packs for your game ***