The Company Details window requires a tax registration number to be entered.  If this is missing, you will see the following error when running the Validate Payroll Data report:

'The Company Details window does not contain a tax registration number, which is required by Revenue'.

1. On the menu bar, click Company/Payroll then Company Details.
2. In the Tax Reg. No. box, enter your company's tax registration number.
3. Click Save.