NSC | Journal Entry > Name Field > Cannot Select Customer
The user is trying to add a customer on the name field when creating a Journal Entry but the drop down list do not show any customer.
Since the currency that will be used in this Journal Entry is Australian Dollar, check the Customer Record if Australian Dollar is added on the Financial Tab > Currencies. If not, add them on the list.
After doing so, the user will now be able to select the customer on the Name Field.
Hope this helped!