Disk Utility error: com.apple.diskutility error3

I've been trying to make a copy of a VHS tape that I burned to DVD using a Sony RDR-VX521 DVD burner. Disk utility was able to see the disk, and I am attempting to create a new image to burn from the DVD using Disk Utility on a 2008 iMac running El Capitan. The first time I tried, Disk Utility saw the DVD, and I started to make the new image. However, upon completion, Disk Utility gave me the following error messages: The operation couldn’t be completed. (com.apple.diskutility error3.); Operation failed with status 5; Operation failed... . I am not sure if this is a problem with the disk produced by the Sony device, or my iMac.

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