After I posted the above, I installed the VS2008 that I had just burned and rebooted as requested at the end of the installation.

I started Imgburn and re-ran the verify and it completed this time in < 5 minutes

I run a very clean rig with almost all startup apps disabled for my video work. Other than downloading the ISO and burning it, I did not run any other programs.

I am going to chalk this one up to a random event and move on.