I have a problem when burning video files to backup using Imgburn. On single layer discs, the discs will not play. They aren't recognized by the computer that burned them and other video players won't play them. The sequence is dvddecrypter, Imgburn, iso file, then disc.
Are you using the old 'DVD Decrypter' or the current 'DVDFab HD Decrypter'? Rip the disk, using DVDFab HD Decrypter, to a folder. Generally, the size of the ripped files is larger than the capacity of a SD blank. Run DVD Shrink, open the VIDEO_TS folder containing the ripped files and 'Backup' to a new folder or image file. The files will be 'shrinked' to the capacity of a standard blank. Use ImgBurn to burn the new VIDEO_TS folder or image file. If possible, use 'Verbatim' brand disks (they should say 'AZO' or 'Advanced AZO' on the package.