DVD Copy Problem

[MI6]

I have TEAC DVD writer on my computer, and I use it for recording my own video materials like wedding partys, birthdays and so. Everything is OK, using Vegas 6 for editing and TMPGEnc DVD Author for DVD authoring, then Nero for burning DVD's.I have try many medias like Princo, Verbatim, Memorex Proformance..... and everything seems to be fine, almost all burned discs are
playable on DVD players but when I want to copy disc to another DVD disc I usually get message
"Data cylindric error"- can't copy. I'm using DVD Shrink, Clone DVD, DVD Decrypter, ISO Buster and other programs but no succsess.So what is the point. Obviesly media is not a problem.
Maybe is something wrong with DVD writer.I upgrade firmware to new one but no results.This is OK for protect own DVD's for copying, but when I want to copy my own DVD's that is a problem.
What to do?
Regards.

[Marvingj]

Data cylindric error means Bad or Dirty Disc.

[Krispy Kritter]

It could still be a media issue or a bad / failing writer.

[bevills1]

Have you tried DVDDecrypter in ISO Mode?

1. ISO read copies image to hard drive.
2. ISO write burns hard drive image to blank DVD.