When I import a video. The video is not read by after effects. The video is a 1980x1080 video that i have edited with another software (videopad). When I import it, at the top left, it shows the video time but says it is 0x0 and 1 fps. It usually shows a pic from the video but it shows a grey box with the sound waves underneath it
The video is an AVI file
Try exporting from Videopad using a different codec.
H.264 (or any lossy codec) is a poor choice for an intermediate file, anyway; you should use a losslessly compressed file when moving a movie from one piece of post-production software to another. Only use a lossy codec like H.264 for the final delivery file, created at the last step of your post-production chain.
The point of using the PNG codec is that it is lossless, meaning that it will retain all quality of the original. H.264, on the other hand, is lossy, meaning that it loses quality with each compression step. That's why Szalam suggested PNG to you.