>Why is it that in the sample ProjMgr of Mere Mortals, the first page contains the data environment object and the business object? While in other pages, it only has a business object and one page has a data environment object only? I'm confused on when do I need to place these two objects or when do I need only one of them and which one.

Where are you seeing this behavior? Usually, all you need to include is the business object itself, as it will manage the data environment that it needs.

Chris.