Thats probably because you need to give it time to process. After uploading something the video needs time before anyone can view it. Give it about 10-15 minutes then come back and see if it's ready. If it's not then go to "My Videos" and see it in there. If there's an error under it then it will describe what your problem is. Most problems that would occur would be the video being over 11:00 minutes (too long) or not uploading it with the right file type.