Adding A Vendor Bill w/ Multiple Line Items

Evening All,

I'm hoping this turns out to be a relatively simple answer. I've scoured the forums, as well as SO and any other resource I can find but have not found answer.

I'm doing what I would describe as something that is fairly simple. I want to add a vendor bill with a single line item. Most of the line item information will actually be identical for each bill (though this is besides the point). Originally I was getting the message that I needed at least one line item before adding the bill. No problem, I figured that out. Now the issue I'm having is that it's not accepting what I provide as a line item. I believe this is because I'm not specifying the account record information correctly, which in turn