I have done something similar to what you are trying (getting data from Excel into a Processbook trend). I had to create a dataset and then fill the dataset with values based on an SQL query. You also need to make sure the you have a DSN connection to your database otherwise you won't get any data, but it sounds as if you have already done this.

I can send you my Processbook display with the VB code behind it, and that should help you out a bit. Just email me if you want it. You can probably remove some of the code thats there as it might not be applicable for you but the basics of getting the data displayed is there.