Line 6 if Form 2106 Employee Business Expenses is a total of other entries - you should not have to (or be able to) make a direct entry there.
Are you itemizing deductions and are you eligible to claim "Unreimbursed Employee Business Expenses"? Federal returns have strict limitations, but some states allow this. See Unreimbursed Employee Expenses
If you are not itemizing and/or are not eligible to claim unreimbursed employee business expenses, enter "0" where the program asks you to complete Line 6 of Form 2106. Another option would be to delete the Form 2106 - re-enter it if you are itemizing this deduction or leave it out if you are not itemizing this deduction.