Hmm....maybe a hint will help.

The four guys are eventually set free, but it takes a few moments after they are buried and the puzzle explained before the correct answer is given.

That may give it to someone now, good luck.

Hmm....need more help eh....ok.

There are two possible scenarios here. With two colours of hats (white and black) here are the two possibilities:

The hats are distributed as follows:
1) B B W W (or W W B B)
2) B W B W (or W B W B)

Scenario 1) The guy is the 2 position would see two hats of the same colour ahead of him, therefore his hat must be the opposite colour! Easy.

Scenario 2) ???? Figure this out, and you'll have the answer.