Nero burning software didn't ask me to finalize the session or anything.
I think when you burn an iso it automatically does that. (not sure).
Tried a CD on a machine, it worked. Tried the same CD on another machine and it didn't work. Tried a DVD on the machine that worked for CD and it did not work.
Strange.
Do you have at least Solaris 8 installed and running on the system(s) ?
If so, then as any user, do ...
$ iostat -En
Find the entry for the optical drive and let us know the brand name
and whatever it might list for "Revision" (which happens to be its firmware version).
Early Netra 140x systems shipped with only a Toshiba CD drive
and later ones shipped with a Toshiba DVD-ROM drive that had issues
reading DVD media.
The solution was up update the DVD drive firmware, [url=http://sunsolve.sun.com/search/document.do?assetkey=1-21-111649-04-1&s earchclause=m1401]using patch 111649[/url].
If you have a non-Sun drive in there, I would not be able to give advice.