Your employer has already excluded from the amount of wages reported in box 1 of your W-2 the amount of your elective deferrals to the 457(b) reported with code G in box 12 of your W-2. You do not get to deduct is again on your tax return since that amount of your wages was never included in taxable income to begin with. the same goes for your wife's 401(k) contributions reported with code D in box 12 of her W-2.
Enter amounts shown in box 12 of your W-2 only in box 12 of TurboTax's W-2 form, nowhere else in TurboTax. The same goes for your wife's 401(k) elective deferrals. Nothing about the 457(b) or the 401(k) is to be entered under Deductions & Credits.
