Who are you buying traffic from? This was brought up in another thread — the traffic from some PPC engines is questionable.
http://www.casinoaffiliateprograms.com/bb/enhance-interactive-ppc-any-good.7033.html?
http://www.casinoaffiliateprograms.com/bb/ppc-engines-that-still-accept-casino-ads.6204.html?