My early 2008 has one button underneath the trackpad and it's only for clicking "left clicking", it's just one wide button. It doesn't have right click, so are you sure you could do that? It doesn't sound right, and i didn't think any mac had a left and right click button? Just making sure.. Because it makes sense that your right side acts like the left side as the whole button should have the same function and not two..
Too "right click" i just click with two fingers on the trackpad instead of one, that pops up the menu for me.