Well, let me be blunt and say that Norm couldn't save this movie, but not for a lack of effort, or rather, lack of the beloved Norm MacDonald charm. His voice work in this film contains all the understated and dry expressions of wit that fans of his stand-up and late-night performances have loved for years. In his portrayal of Fang, a 600-year-old vampire that has been transformed into a dog, he makes no effort to create an accent or enunciate in a way we would expect a Transylvanian canine to. In fact, Fang the Vampire Dog IS Norm MacDonald. Yes, he likes to eat red jelly (because children's cinema has sunk so low we now need euphemisms for blood.) And yes, he burns in the sunlight, but otherwise this dog is complete Norm, and the movie is much more enjoyable for it.
The Internet is full of ridiculous whining and questioning about why Norm chose to take this role. The question fundamentally misunderstands his role as a comedian in the world of entertainment. Ultimately, his job is to make people laugh, and that is something he accomplished as a dry-witted jelly-eating terrier. While Vampire Dog is overall a horrible and cliched film, Norm's voice made it better. I haven't managed to hear his work in 2012's The Outback, or any of his other previous voice work but I look forward to hear him do more voice acting in the future.