A blank Line 57 means that you do not owe Self Employment taxes.
Look at Line 43 and Line 44 and Line 63. Line 43 is your taxable income and Line 44 is the taxes owed on that income and Line 63 is your Total Tax. Then look at Line 74 which is your total tax payments. If Line 74 is less than Line 63 then the difference is the amount you owe in federal taxes, as shown on Line 78.
