Hi,
What format (video) discs does it reject....pressed dvd-rom,DVD+R,DL etc or all of them?Maybe it dislikes a particular disc format,say DVD+R.
Also try different brands.
Try video discs with diff. formats,or burn one and see.
Also look for a recent firmware.
If all else fails,open it and clean the lens with a soft clean moist cloth.
Finally dump it and get a new one.