Nero burning unreadable blanks?

Hi all,

I just picked up a NEC 3500 and a couple of Philips DVD+R 2.4x

Updated to the newest version of Nero as well as 2.18 firmware for my burner.

I burned a DVD ISO data disc, using a new multisession, without finalizing/closing disk.

Burning was complete.

I tried browsing the DVD, but it shows the disc as empty in explorer.

I viewed the DVD with Nero and the session was comfirmed as burnt.

I tried to continue the multisession with my DVD but got the error:
“Illegal Disc… Could not perform end of Disc-at-Once”

So there were my two problems…

I’m on WinXP with SP2.

Thanks you advance to all.