The crew was running in hole with 3 ½” cement stinger on 5” drill pipe. The number of singles to be run were calculated and laid out on the pipe racks. While verifying the amount, it was realized that one too many joints were on the rack. The joint was rolled off the rack onto the ground and the Forklift Operator was told to remove it. For some reason, the joint was not moved and the Assistant Driller thought the single had rolled off the rack on its own. The joint was put back on the rack. The Driller continued RIH and ran into bottom of the hole. The pipe buckled and broke.