IM NOT SURE IF THIS WILL FIX IT BUT I HAVE HAD THE SAME PROBLEM A FEW TIMES. I REMEMBER SAVING THE FILE AS A DIFFERENT NAME, AND CHANGING THE CODEC FROM AVID MERIDIEN TO ANIMATION. FOR SOME REASON THE AVID MERIDIEN WAS CAUSING A PROBLEM. ANOTHER PROBLEM MIGHT BE THAT YOUR COMP SETTINGS DO NOT MATCH UP WITH YOUR CODE SETTINGS, FOR EXAMPLE I THINK THAT AVID CODEC WANTS A 720X486 SETTING, AND IF YOU TRY TO RENDER WITH AVID MERIDIEN CODEC WITHOUT IT BEING THAT WAY IT WILL ERROR.