I don't know where everyone gets their numbers. However, according to the North Carolina State Board of Elections latest numbers, which seem fairly updated, the break-down of the North Carolina primary electorate looks like this:
White Democrat: 41%
Blacks: 30%
White Independents: 27%
Others: 2%
So. If everyone turn out in equal numbers and Clinton wins White Democrats by the same margin as in Pennsylvania (2-1) blacks break their usual 90-10 for Obama and white indys split 50-50 (again, as in PA) and others do too it's almost exactly 55-45 for Obama. Doesn't seem completely unthinkable for Clinton to do a little better then?
Why should White Independents turn up in equal numbers to White Democrats and Blacks? That makes no sense.