Great advice1 Sorry for the delay in responding, I was trying different media. Various dvd formats (+R, -R, RW) did not fix the problem (on either PC), but may have led me to a solution ( have not had time to try, but I shoud know by tomorrow). I even tried a different PC with Centos, rather than Ubuntu, (and K3b and Gnomebake burn programs) but I get the exact same results on both.
Since I did not have an md5sum (from LXF towers) for the iso, I could not be sure that the file on my PCs were in fact legit, so I downloaded a similar size iso from ubuntu via torrents to both PCs and check their md5sums against the ubuntu supplied md5sum file with a match in both cases. This made me think of the common traits of both machines -- at least those I suspect. They are:
Brasero - opens when I insert a blank DVD, then I opt for "write to disc"
TSST SH-S203B and SH-S203N (your media hint led me here)
In the past, when I ran the "check disc" utility on a bona-fide LXFDVDxx, it was successful. So maybe by DVD burner can correctly read, but not write, the DVD. I even borrowed on burner from my neighbor but with the same results. If you havent guessed by now, it was also a TSST brand but model SH-223. (I even tried to flash the firmware on my 203N with the SB01 (downgraded it from SB02) firmware).
Thats where I am just now. I acquired another Burner, a Lite-on model iHAS124-04 B which I will install and try with results to follow.
Still having fun, and am learning alot, thanks!