Playback problem with disks burnt in Nero

So I started to back up my DVD collection. I ripped some disks using DVD Copy. Burnt one using Nero, which worked great. Then I tried the next two and had a problem. They worked perfectly using my XBox and another DVD player, but will not play on any computer I try. I have used multiple DVD playing software (including Power DVD, Windows Media Player, and VLC). What’s wrong. I could see if it wasn’t playing on an XBox, but why not on the machine that burnt it in the first place?