It could be that you paid property tax in a previous tax year, or the program is making sure you don 't miss any potential deductions. The term "property tax" can also apply to personal property such as an automobile, boat, RV or airplane.
In any case, you should answer the question as it applies to you. If no property taxes were paid, enter "0" and if asked when you paid those taxes of "0", enter 12/31/207.