i've been playing around with the activity and download windows, and it seems like it is possible to play youtube videos directly from my mac's harddrive. for example, when you go to this pages' activity meter ( http://youtube.com/watch?v=HRJB_tMcbYg ), the video is the one that 8.7 MB. when I transfer that video to the downloads window, the video goes to my desktop. when I try to watch the video, i get the attached error message. i really want to be able to watch youtube videos when I travel, for example, so please help me out!!