The easiest way is to make a temporary copy on your hard drive. Start ImgBurn. Click on Create Image File from Disc. Use the dvd drive (with the unencrypted disk in it) as the input. Make the ISO file on the hard drive.
Now put in a blank dvd, start ImgBurn and hit Write Image File to Disc. Set your burning speed, use the ISO file you just made as input, make a label and start burning.
Once done you can simply delete the ISO file from the hard drive to save space.