Trouble began when Lockett was given his deadly dose of the drugs. They didn't seem to be working properly, so prison officials tried to halt the execution midway. Lockett ended up dying anyway--supposedly from complications of the execution procedure--so the execution was considered a failure because Lockett died, although that's the whole reason he was strapped to the lethal injection table in the first place. Because of the complications, Warner was given a stay and was not executed.
The other bit of irony is the fact that Warner, who was not executed, ordered and was given a last meal while Lockett, who WAS executed, did not enjoy the last meal ritual. Lockett did try, but was told that his order of steak, shrimp, baked potato, garlic toast, a whole pecan pie, and a bottle of Coke went way, way over the state's $15 spending limit. Upset by this, Lockett decided to pass on the last meal altogether.
Warner, on the other hand, ordered an approved last meal of boneless chicken wings, potato wedges, cole slaw, fruit cocktail, and Coke. He was given his last meal and ate it despite the fact that his execution was later cancelled.