my dyson makes a noise?

hey i just put my dyson on and its makeing a rattling echo noise down the base od dyson on looking the filter compartment doesnt fit correctly in position leaving a gap where the rubber seal is ment to join the pipe on the hoover middle will this be the reason and would it be easy to fix the person i bought it off has offered me a full refund or sum discount if i get it repaired myself, any advice....