Brown dwarf conspiracy theory vs. simple math

Here's an interesting conspiracy theory about the existence of a brown dwarf nearby. It's very likely that we have one or more brown dwarfs nearby in the sense that 1 light year is nearby, but this page is mixing in popular conspiracy with a dash of science and attempting to pass it off as fact. Here's what it claims:

- An object was spotted in 2002 and NASA was warned not to tell the public
- It's "supposed to hit the Earth or Moon sometime in 2012"
- It has been classified as a planetoid, and a brown dwarf. (Uh, a planetoid is a small planet while a brown dwarf is insanely massive compared to all the planets in our solar system including Jupiter)
- It's moving toward us at a speed of 45,000 MPH.

Sounds fast! Oh wait a second, let's try out some simple math to see what this would mean.

Google, how many hours are there in a year? 8765. Okay, so how many km is that over two years?

8765 * (45000 * 1.6) * 2 = 1262160000

Wow, so this object would be a phenomenal 1.2 billion km away. Or wait a second, how far away is that in AU?

... 8.4 AU. If we give it until December 31 to arrive then it gets another 2 AU, placing it at 10.4 AU from the Earth. That's a bit farther out than Saturn. So according to that page there is a body out there the size of Jupiter (brown dwarfs are all about that size) and at least ten times the mass (the lower limit for a brown dwarf) at the same distance as Saturn (easily seen with the naked eye) that nobody has spotted.