If you're talking about the actual teletransportion of matter, there's one equation that keeps coming to mind...
e=mc^2, where
e is the energy released
m is mass
c is the speed of light.
Basically, converting even a small amount of matter releases a lot of energy. Approximately 50 grams of any kind of matter converted to energy at 100% efficiency releases 1 megaton of energy. A megaton is the amount of energy release by detonating one million tons of TNT (~4.2 x 10^15 Joules), which is equivalent to a large H-bomb.
Short answer: You'd better have a damned good energy containment system!
Then there's the issue of tearing something apart during the energy conversion process. You first.