Why is it that "Mac OS X Snow Leopard can't be installed on this computer"? I'm trying to install Snow Leopard on a MacBook (32-bit, Dual Core, ca 4 years old).

I am presented with: "Mac OS X Snow Leopard can't be installed on this computer."

Is it because of the 32-bit architecture? Should I just go with Leopard instead of Snow Leopard?
Check to make sure you have enough RAM, Snow Leopard requires 1GB of RAM.  Snow Leopard does not require a 64-bit processor.