You could ask your hosting company to fix this problem for you.
Yes, I should. Altho I am more interested in how and when this happened, and how to prevent from this to happen in the future.
When you installed the video module and the video_upload plugin drupal automatically created a folder to store the videos (a 'video' folder under the folder you configured for uploads).
The newly created folder has been created by Drupal which is PHP code executed by the Apache server which run under an different Unix user.
Then the new folder has been assigned to the user which run apache.
Fabio