The DME driver wasn't looking for your airline tickets. DME drivers never require airline tickets or airline boarding passes.
He was looking for your DME transportation vouchers. These are scanned when you board the motorcoach at MCO and collected when you board at your resort. (If you lose them, the resort can print new ones for you. But this needs to be handled before you try to board the motorcoach.)
It sounds like there was a misunderstanding between you and the driver.
You barely made it through the airport lines and to your gate in time, even though you left your resort approximately 3 hours before your flight? (Just think.. Some people feel they can leave their resort an hour before their flight!)