Other mistake: After the concert, when Dewey is telling Gordon how awesome the lights were, Eleni calls him Jack. The actor that plays Dewey is Jack Black. (This mistake is mentioned in the Kids Kommentary [sic].) (01:35:40)
Other mistake: During the credits when the band is having class, Dewey starts singing, "Credits got to roll. Look at that name there. I do not know that guy." While he sings that he pretends to follow one of the rolling names with his finger. Only problem is he's going the wrong way. He's scrolling down, but the credits are scrolling up. (Though an explanation is offered on the commentary, this is still a mistake within the film.)
Answer: The song isn't on the soundtrack, and I can't find anywhere in the film where Jack sings lyrics that even sound like Tears. I don't think it's true.