HI Byran,
I am not talking about data declaration inside method ZIMRA_SUBMIT_INVOICES. I am asking about parameters in the method. When you double click on method, Click on 'signature' button of the method (or Shift+F9). It will enable parameters display. Then check type of INPUT. This type should match with the one you declared in your report.
Refer below screenshot:
Whatever type declared in method, make same in your report for variable 'INPUT'.