Kempter TITJUR Opinion of Mr Advocate General Bot delivered on 24 April 2007. # Willy Kempter KG v Hauptzollamt Hamburg-Jonas. # Reference for a preliminary ruling: Finanzgericht Hamburg - Germany. # Export of cattle - Export refunds - Final administrative decision - Interpretation of a judgment of the Court - Effect of a preliminary ruling given by the Court after that decision - Review and withdrawal - Time-limits - Legal certainty - Principle of cooperation - Article 10 EC. # Case C-2/06.