Nobody can tell you anything without proper system info or other technical details. This simply looks like you have an issue with hardware acceleration on your system, either on the display side or when decoding your footage. At the same time this could be as trivial as one of your source fiels being damaged.
Try identifying the layer that is generating the error your timeline by turning off or deleting one layer or effect at a time. When you have identified the layer do the following:
In the Project Panel select the footage that is giving you the problem so we can see the properties of the footage. Select the footage in the Timeline and press the U key twice to reveal all the modified properties of that footage and then take another screenshot so we can see what's going on.
Then give us your system info and version of AE down to the last decimal point. It's probably the codec used for the footage or an incompatible effect. Without some more information it's impossible to even guess what's going on from the info you provided.
U were right i checked all of my footage, one file was in the timeline that made the error.
I deleted the file and now it works fine.
Thanks for the reply