He named his pet the same name as a player, thus the parser thinks it is a player. if there is a player and a pet with the same name there is no way to tell which is which from the log. Thus the only way to "fix" it is to rename the pet something else that isn't a player name. Or convince Daybreak to change the log output to differentiate the damage messages.
In version 1.0.3 if there was a player and a pet with the same name, it would count them as a pet and not a player. I changed it to work the opposite way on purpose to stop people from changing their pets' names to a player name with the purpose of making the player show as their pet. (Yes, people really did that).
He really shouldn't be using 1.0.3, the parses will be incomplete / inaccurate.