In the Ad submission page, check the right hand side option under “Ad Location & Contact”.
If the “Use address set in profile section” is checked and there is no address defined your profile, you will see this message.
You will also see this message if the option is not checked and you haven’t defined the ‘Precise Location’. If this is the case, where it reads “Precise Location”, begin to type the desired product location and then try resubmitting the ad.