That is true, MB. They probably do have a limited number of words they can use, but the way it's written is just weird. They could have described the same exact thing with less words: "The film is about vampire Barnabas Collins who lives in a secluded mansion in a sleepy coastal town." Maybe they just wanted to confirm that the setting was indeed Collinsport. ;-) When I read that description, though, I think something along the lines of
A Series of Unfortunate Events, where some kids stumble upon a creepy old house and the reclusive vampire inside.
And if we are to speculate further using this strange description, we might also be able to assume that this is the only plot detail everyone working on the film has been able to agree upon:
"Well, we know there is going to be a vampire named Barnabas; and we know he lives in an old house in Portland..."
"Not Portland! Collinsport!"
"Right. Collinsport. And then there is this werewolf ghost..."
"No! That is in the sequel!"
"Oh. Right. So we have a vampire named Barnabas living in an old house in... Collinsport."