First thing, I recommend checking all the lines. There could be some mistake you made, like the above-mentioned having someone else claiming the child as their dependent. In that case, you legitimately owe the $4800 (that is, unless you are willing to go through a big fight to claim your right to not pay income tax at all. Technically, you don't have to pay, but it is a huge hassle and they will wrangle the law to get you into trouble anyway).
If the return is clean, you are in for a kangaroo court. They have been known to arbitrarily assign larger amounts of debt. You pay the original $4800, and they claim there is another $200,000 or more in penalty or in additional debt. Usually, at that point, it is because they want to ruin people's lives and not because you actually owe that much. The "tax courts" are rigged so it is usually unwinnable for the victim.
Thanks a bunch, Abraham Lincoln and Woodrow Wilson!