The error message is caused by a missing workplace postcode in the employee record for freeport or investment zone employees. To add the postcode code follow the steps below.
Note down the employee listed in the error message.
Click Payroll, then click Employees.
Find the relevant employee, and click Open Employee.
Click the General tab, and enter the workplace postcode.
Click Save and Close.
Repeat steps 2-5 for any further employees.
Once updated, you will need to run a save and process to update the postcode on the FPS.