Here's the progression of thoughts.
1) Messed up database format is difficult to decipher.
2) Difficulty in deciphering the format, leads a forensic analyst to mistakenly conclude that the site was visited 84 times instead of just once.
3) Assume that Jury reaches conclusion that Casey Anthony killed her daughter using chloroform. Thus the choice is then whether it was simple manslaughter and she gets a few years in prison, or it was premeditated murder, and thus eligible for the death penalty.
4) Since the suspect visited the site 84 times, this helps lead to the jury concluding that the killing was premeditated murder, and thus Casey Anthony should be put to death.
5) Thus, as the result of a bad database format, someone was put to death instead of just serving a few years in jail.