Thanks to some assistance from Csleesburg, we've discovered a problem with the way profiles are loaded after installing African Adventure.
If you have been playing Zoo 2 or ES under a player profile that you created (anything other than "Default Profile"), when you load AA for the first time "Default Profile" will automatically be selected. When playing AA for the first time, be sure to check that you are on the correct profile. If you have always been playing under "Default Profile", this is not an issue for you.
If you've played through the African campaign and discovered that your old unlocked objects are missing, this is most likely the cause.
We apologize for any inconvience.