Similar report: https://itch.io/post/1502470
Both errors are the same type(the first line), they seek to retrieve data at an index (specific location) from an value of type 'Nil' (a type with only the value 'null'). The second lines of each error give the file path, and the line number in the script where the error occurred. Given that both 'id' and 'race' are members of the person class, the data needed to lookup a person was improperly stored or used, so the core of the error is probably somewhere upstream of these error messages.