Most likely your disk is scratched or damaged. Try a known working disk in the player. Alternatively your DVD player may be malfunctioning or installed with a faulty cable.
Change the scan format. In the menu select NTSC instead of PAL, though the screen might be hard to read. You might try unplugging it as well, to reset it.
There might be dust or dirt on the dvd, remove dvd and clean it with a soft cloth and try again. If that is not it look at the dvd for scratches, if that's the problem the dvd is no good. Or maybe the lcd screen is damaged.
Well, there could be many reasons why that is happening. One of them is that the disc could be scratched or damaged. An other factor could be that the laser in the DVD player is broken.