Can't validate TI 2009 spanned DVD backup

I'm in the process of backing up my laptop using TI 2009 bootable media and the writing process has finished with 1 DL DVD full and part of a second. I had asked to Validate the backup archive but when it started that, an error message popped up:

"Error opening the file.
Please insert the last media of the backup archive and click Retry to continue.
Otherwise click Cancel to stop the operation."

So I removed the second disk and put the first in, and I get the same error with either disk.

What is wrong? Thanks.

 

Since I can't seem to delete this post here is the solution:

The DVD-R drive I was writing to is external and the disks were just taking a very long time to spin up before Acronis could read them.

I just wasn't waiting long enough for the DVD's to come up to speed.

Duh.

 

Glad you didn't delete it. The answer may come in very handy to someone else.