J.M.
How exactly are you doing this? Make the jello as directed then pour into a 13"x9" pan. Chill until firm give it a couple hours. To remove dip pan in warm water about 15 seconds. Use the cutters in the pan.The warm water helps lift them out.Or after dipping in warm water run a knife along the edges and flip it over onto a cookie sheet or cutting board.It may help to have a bowl of warm water to dip the cutters in too.Good Luck!