Have you already purchased the game?  If not, then you would probably only be able to play the game for a one hour trial.  If you have purchased it, then you may need an unlock key that you would get from PF if you purchased it from here.  If that's not the problem, then maybe like the other person mentioned, you need to install Activ-X.  Good luck!

The add-on restaurants are usually only around 10 levels and if I remember usually were priced around $5.95 per add on.  Maybe they were a bundle pack of like 2 or 3 for one price that you were trying to buy, but just one add-on should only be around $5.95.