About tribe- i made my tribe and only 2 first guys that get there, can watch the videos, what is the problem?

Just change the ranks around

Everyone needs to be in the tribe house when the video begins. If it's already playing when they join the room, it won't work for them.

i have tried both things.... nothing happens only 2 firsts that get it working and i have tried changing ranks but still nothing

What I've experienced, is that when you played a video with mouse1 and it ends, when mouse2 joins and you try to play a video, it does not work for mouse2.
Try to re-load the tribehouse when others come in, simply "/np" will do.
If that doesn't work, give them the link to the video and see if they can watch it on youtube. There's a chance that they can't watch it due to it being blocked for their country.

Even so, sometimes my tribemates can't see the video, while they're able to watch it on youtube, I re-loaded the map, etc. Relogging has solved it before, though I'm not sure if that's the best/easiest thing to do.

Try re-loading the map for now.