T3-2 and Solaris 10 Problem

Hi Guys,
I got a unique (and wierd) problem with trying to install Solaris 10 off of a DVD on a T3-2. You boot cdrom, it goes through the questions and then when it comes to ask you if you want to install using nfs or dvd if you pick dvd it comes up with an error - ERROR: The disc you inserted is not a Solaris OS CD/DVD. then halts

Wierdly you can install Solaris 11.1 or Solaris 11.2 (one is CD, one is DVD). You can also install 10 using a flash archive via NFS.

Tried releases of 10, 9/10, 8/11 and 1/13

Any insights into why it does this would be gratefully received.

Thanks in advance

Martin