When i put a dvd in it says attention you cannot play this featuer whitle driving

The video feature is supposed to be available only when the car is not moving. So there is a wire coming out from the stereo that is supposed to go to the parking brake switch, that's the same switch that will make turn on the brake light in you dashboard.
If you cannot find that wire in your car's harness. Then you could easily fix it (under your own responsibility), by connecting that wire from the stereo to ground. Than will make the DVD feature to work on any condition.
That's how I made it work, I think it's okay as long as you connect an auxiliary screen for the kids to watch on the rear seat.

It is improper for you to insert a video while driving. It is most likely to cause some distraction to you who is driving and as such the player may have been integrated with some sort of sensor which detects whenever the car is in motion and enables the player to know that you are driving.
Have you tried to stop driving and see if it works? If you haven't tried that you could try it out and see if it works fine then.
If not, you have to go through the manual to see if there is any information on how to use the player while you are not driving.
It may require you to put in some kind of command or to flip a driving/not driving switch somewhere around the player.
let me know if you need additional information and thank you for using fixya/.