Theo says he has a 64 bit processor and he's running 32 bit Windows, and thinks that might have something to do with it. Leo says it shouldn't matter that he's using a 32 bit version of Windows on a 64 bit processor. All processors are 64 bit and can run 32 bit operating systems. Theo says whenever he initiates the setup for Windows Home Server, it tells him the version he's trying to install isn't compatible with the version of Windows he's running.
Since Theo could only find a 64 bit version of Windows Home Server, he will need to first install the 64 bit version of Windows Vista for this to work.