This error appears when submitting a service request and came as a result of turning off the USD currency under Organization Profile -> Currencies.
I wanted to make use of the currency field in a business object and only have AUD as the dropdown option. I didn't realize all service requests seemed to be tied to the USD currency being active even though we do not make use of pricing on our Service requests.
Is there another way around this perhaps if I can change our service requests to use AUD instead of USD? (I don't appear to have an option for this).
I would recommend making 2 changes:
Log into the Admin role
Select Configure Application
In the left bar, select Organization Profile - Account Information
Set the preferred currency to Australian Dollar
Select Pick Lists
Open Pick List CurrencyCodeTypeValidation
Add a constraint (using the green plus at the bottom)
Add the constraint 'Where Code equal to AUD'
Save the pick list