Combine cake mix, melted butter, flour, eggs, pumpkin pie spice, and vanilla in large bowl. Beat with a hand mixer for 1 minute, or until well blended. Stir in oats, walnuts and dates. Drop heaping tablespoons of dough onto an ungreased cookie sheet, spacing cookies 2 inches apart. Bake for 10 minutes, or until edges begin to brown. Cool cookies on cookie sheet for 5 minutes and then transfer cookies to a cooling rack or platter.