There are many times when errorsWarnings, yes. Errors, not so much.
But this one is an index off by one error. Someone coded it so that it looks up index 4 in a 4 item list that starts at 0. In other words, it has items zero through three, and the code wants the fourth one. It should ask for three, since it counts from zero, but instead it's asking for 4, which doesn't exist.
This is a moderate problem, because as Rui pointed out, the dialog isn't being properly terminated because of the error.