I gotta admit, I sort of like the idea of a vampire not being able to digest Kal's Kryptonian blood. However, that one good idea does not a good story make, especially since-logically-his solar blood should have killed (or at least cured) the Werewolves in the first part of the story.
Furthermore, it begs the question: as soon as Superman knew the guy was a Vampire why the fuck didn't he fly Lois and Jimmy home instead of spending the night there? Basically, Superman is dumber than a character in "Scream" at that point.
