Error 1305 typically indicates that there is an issue reading from the DVD. You can try the following to resolve error 1305:
Verify the DVD is clean and free of any smudges/scratches.
Try another copy of the same DVD.
Re-start the update from a different/external DVD drive.
If you have tried all of the above, it’s possible that the DVD, or DVD drive is defective. Please contact support for further assistance.