Calculated lookups based on dropdown selection

Hello,

I'm trying without success to do the following...

I have a portal with a Artist table as context. I have related another ArtLabourItems table in another file to the Artist table.

Then I have a ArtLabourType dropdown field in the portal that defines an automatic value list from the ArtLabourType field in the ArtLabourItems table. This works fine.

There is also a Price field in the portal that is defined as a calulation. When a ArtLabourType is selected from the dropdown I want the Price field to lookup its value via a calulation from the ArtLabourItems table.

Basically I just want to select a value in the dropdown and then have other portal fields automatically filled in.

Right now when I select the "One Hour" option from the dropdown I get a "?" in the portal Price field when using the following calculation for the Price field...

Case(

ArtworkLabourType = "One Hour"; Lookup (ArtworkLabourItems::ArtworkLabourBasePrice);

ArtworkLabourType = "Elaborate";"1000";

"0")

How do I get this to work?

Thom