Same problem here; I got a W2 with the income listed in the Federal box but the State Income box was blank. The federal amount was included in my NJ wage income.
When I entered 0 as the state income in the W2 Box 16 Turbo Tax removed the amount from my NJ income. I guess the computer doesn't assume a blank space and zero are the same thing.
Box 15 did already have the state name and ID number filled in.
