Retaining wall analysis & design (AS4678) - Expression error: undefined variable '_LocaleFile'

Attempting to re-run an old calculation that references the generic System Library results in the error message: undefined variable '_LocaleFile'.

To resolve the problem either:

1. Insert a new calculation in a new document. Open the variable manager in the original document and use Select All > Copy. In the new document open the variable manager and use Paste to populate with the copied variables. Calculate the new document.
2. Delete the old calculation field, re-insert the calculation in a new field and then re-calculate. The first time the calc is re-run may result in other errors; these can be resolved by clicking Continue and ensuring that all the buttons and options have been clicked and confirmed.