Backup CD/DVDs have redundancy error!!!

[NLightened1]

What am I doing wrong? Can someone help? I copy the contents of the game (PC) CD/DVD to the hard drive, and then burn it to another blank CD/DVD and when I attempt to run the backup disc it works for a few seconds and then I get a message: Data Error (cyclic redundancy check). Prior to burning the disc it worked fine. However, afterwards I get this error. Is this common or is this just a batch of bad DVDs? I tried to run DVD X Rescue to recover the data, but it's 99.9% hard error. Can anyone help me with this? The games that I have attempted are Rainbow Six Vegas, Titan Quest, and Swat 4. Thanks for any help!