Some older CD and DVD players just won't play computer-burned CDs period. Others are picky as to the color of the media and if the blanks you're using aren't silver then that could be a problem. Lastly burn speed is also an issue, I've had better luck with discs burned at 2X than with max possible, especially when playing them in my car CD player.
To answer your other question a VCD is a video CD, a way of putting video on a CD. Many new DVD players play VCDs too, although many do not. VCDs have never really caught on in North America although they are very popular in Asia.