Add spaces: Iftheadministrationisfinewithyousellingstuffatthebooth,youhavetofindoutwhetherthereisastateorlocallawthatprohibitsthis(especiallyiftheeventtakesplaceonaSunday).
If the administration is fine with you selling stuff at the booth, you have to find out whether there is a state or local law that prohibits this (especially if the event takes place on a Sunday).