straightforward goof - I can't see what's wrong with the submission

I submitted a 'goof' entry for Dennis the Menace ("The Power of Positive Thinking" that is pretty straightforward: "When Prof. Dobkin learns Dobie's full name, he analyzes it in his mind and congratulates him on having "a splendid name . . . five consonants and six vowels, a wonderful combination." Dobkin has it backwards: DOBIE GILLIS has five vowels and six consonants." I marked it as a 'factual mistake'. I can't see what's wrong. Please help.