Are you sure the owner haven't uploaded the videos by himself?
A solution for you would be to create a new PHP File in your htdocs with name "Videos.php". (I guess you're using subtopics right). However, tell the videos.php file to read the file "Videos.htm", you need to create another file with name Videos.htm also.
Tell the players if they want to upload a video, they could send it to you and you just paste the html code in that file.
Or are you pretty sure that it's possible for the players to upload a video there from their account? (Sounds very riskful, in case of alot porn movies would appear there, lol).