Dude, are you the guy with the mobile home? Is your roof made of corrugated aluminum? You might want to try this repair from the outside instead.
You need a piece of aluminum or whatever metal/material your roof is made of, and it should be bigger than the hole you're trying to fix by maybe three inches around at least. Once you know where the patch needs to go, apply a good amount of waterproof silicon caulk around the hole, and press the patch over the top of the silicon, making sure that you can see the caulk squeeze out all around your repair. This lets you know that you have made a water-tight seal. (Remember that your repair piece has to match your roof exactly!)
Is your mobile home insulated at the roof? Can you screw into your roof from the outside, and not see the screws poking through on the inside? If so, you want to buy enough self-tapping, waterproof tech screws to secure the new piece to your roof. These self-tappers look like screws with small rubber gaskets attached to them. (You might ask for gasketed sheet metal screws, too.) Use a screwgun and drill through the replacement piece and into the roof of your mobile home. The rubber washers will stop rain from getting into your roof as well. If you can't screw into your roof, then set a weight on your repair until the silicon sets up.
You can TRY to fix your roof from the inside...but most likely, it is leaking from a hole...somewhere...and the water is showing up somewhere else. If you absolutely know where the leak is, you might also try using epoxy putty. Get the stuff that you knead in your hands until both parts are blended, then try spreading and pushing the putty into the crack. This stuff could work for you as long as the hole isn't very big.
If you are leaking from a sky light or a vent, you definately want to fix this from the outside.