Error in the Code last week and this week. Plus Promo has ended..

Ok for 2 days now I have gotten There was an error in the code you entered, is the message that keeps popping up. I've tried 10 different codes with the same result. I put in approx. 40 point or so and then got this message, I have thrown out probably 50-75 codes either from Coke can packs, or Diet Coke Coke Zero Caps and have cleared my cache, I have rebutted computer, I have signed in signed out. Why am I getting this? I know I have been saving for some time but really they should expire. Although I through out many more that said Promotion Ended. Please HELP.. I have been saving because we go through a lot of Coke and the limit of 100 points doesn't take long for us. So the codes have been piling up..