Apple Composite AV Cable

I purchased the composite cable to watch TV shows and movies I downloaded to my iPhone4 from my at&t Uverse app. It won't play TV shows or movies from that app. It won't play movies or TV shows from the HBOGO or MAXGO apps. either. The only movies or pictures it will show on my TV are ones I created from my iPhone4 camera. What gives? Seems useless since it won't play anything on my TV that I want to watch. What gives? Any ideas from the community? Do you know of a composite cable that will work for from my iPhone4 for watching TV shows downloaded from other apps.?