Hi @Devon Bilsing,
I would suggest that you first get the basic function working without the driver. And then get it working.
=LookupObjectUnitValue(Application Allocation,Cost,Business Unit Allocation Master Data.Business Unit,Application Allocation.Business Support Organization L1)
Looking at your function I am guessing that you are on a report backed by the Business Unit Allocation object and for each Business Unit, you would like to get the total Cost of the BU from the Application Allocation object in the Cost model. (yes I realize that you want the Business Direct driver - we will get to that)
So first things first - are you getting the total cost by BU?
If yes - then the next step is to add the driver:
=LookupObjectUnitValue(Application Allocation,Cost,Business Unit Allocation Master Data.Business Unit,Application Allocation.Business Support Organization L1,Business Direct)
The name in parenthesis is the name of the source object I think and does not need to be specified. When you click on the driver, the name that you are able to edit is the name you should use in the function.
Hope this helps!
Regards,
Sanjay Valiyaveettil