A 54-year-old man was recovering from serious injuries after he was run over by his own vehicle Monday morning, Ashburnham police said. The unidentified man had trouble disengaging his emergency brake when he placed the vehicle in reverse on the driveway of 103 Stodge Meadow Drive, officials said. The victim then fell out of his open car door as the vehicle rolled down the driveway, police said. Officials believe the man’s 9-year-old grandson, who was found in the driver’s seat, may have helped stop the vehicle when it struck a tree stump. A 5-year-old girl suffered minor injuries when she was hit by the rolling car’s open door. Both the man and the girl were taken to UMass Memorial Medical Center in Worcester and are expected to recover fully, officials said.