Tony, much of the information comes from public records and various other sources. It isn't uncommon to find errors. (My own house shows up with incorrect information, too.) It really doesn't matter unless you plan to sell.
To correct the errors, email Trulia. It may take a while but I think they will eventually fix them. One thing you should be aware of, though, is that rooms in a finished basement are not included in the official count (your town hall lists 3 bedroooms and 2 baths.) Sometimes these extra rooms are included in advertising a home for sale, but it should be disclosed that they are in the basement.
Hope this helps!