You have not provided any proper system info, no details about your footage and sequence settings, no nothing else. Just saying that there is an error is not really meaningful or useful in any way.
comp settings: 1920x1080 30fps
Adobe ppro version : 7.2.1
After effects version : 126.96.36.1994
OS: windows 8
PC configuration :
8gb 1600mhz ram
You are several bug-fix updates behind. I recommend installing the updates so that you are running version 12.2.1, not 12.0.0.
[Moderator edit : the new link is https://blogs.adobe.com/creativecloud/updates-for-adobe-premiere-pro-after-effects-and-ad obe-media-encoder-cs5-cs5-5/?segment=dva ]
I'm trying to fix this problem too. Unfortunately the CS5.5 update that appears to be linked on this page is no longer linked. Do you have a new link?