Luckily errors in lottery draws are uncommon. The three shown here happened in 1985, 2000 and 2011, but didn't caused any problems for winners.
During the January 3rd live tv draw in Picton in 1985, a Wintario lottery staffer loaded a ball into the wrong machine. To fix it they unloaded the machine and made sure the correct ball was retrieved in front of the cameras. Video
On Monday, August 21, 2000, a New York State Lottery presenter was doing a live drawing for the evening's Daily Numbers. The man had a problem in reading the three numbers and had transposed the number '6' with the number '9.' Video
On a June 2011 draw, one of the South Carolina Education Lottery draws went crazy as the balls started flying out of a draw tube. The draw was cancelled and redrawn later. Video