second screen shot
The layout you are going to is not based on the same table occurrence (box in Manage | Database | Relationships) as the one into which you are specifying find criteria with the set field steps.
I see: TU01b1_UBDOrders_UniqueLineItems.... in parenthesis in the Go To layout step
and I see: TU01b1_UBDOrders_UBDConfirm...
This means that you are searching for records in the first TO's (Table occurrence's) table that have at least one related record via the relationship from the first TO to the second that match the specified search cirtieria.
I suspect that this means you need either to specify a different layout in the go to layout step or specify different TO's in the Set Field steps.