Do the neighborhoods show up in your Neighborhoods folder in My Documents/EA Games/The Sims 2/Neighborhoods? You may have 2 EA Games folder, just fine the one that isn't empty.
Or do you just have 2 folders? Belladonna Cove and Desiderata Valley (as well as the other EP worlds) would start with letters that come before N. Pleasantview, Strangetown, and Veronaville would be N001, N002, and N003 respectively.
Also, are you able to create your own neighborhood?