DVD Won't Play through VCR

I recently bought a cheap DVD player, and was trying to use it through a VCR, to allow it to play on an older TV with no A/V jacks. It comes through but the picture cycles between light and dark, and loses both horizontal and vertical sync every few seconds. Works fine when connected directly to the A/V jacks of a newer TV. Is this some kind of copy protection, and is there any way around it? Thanks.