(Nero+PioDVR107) = Unknown data track?

Hi all,
I have a Pioneer DVR107 and use Nero to burn my CD-R, DVD+R, DVD-R. Many of the disc i burned, no matter DVD+/-R even for CD-R format, quite a number of them when read under my Pioneer DVD writer is empty. I try to read it under different DVD Roms from my friends the disc is still empty.
Then i download the CD/DVD Diagnostic Evaluation to have a check for those discs i burned, there were detected as “unknown data track”. At first, this happened with my DVD+R disc, so i tried out DVD-R and CD-R, for both multi-section and finalized disc test, the result is still empty :confused:
Is there anything wrong with my drive or Nero ??
And is there any software which can recover “Unknown data track error” disc ??CD/DVD Diagnostic cannot even display any file from the discs…
Thanks… :sad: