ps2 back up problems

[stumpy]

I am using a pioneer 105 with primo and have downloaded the update so primo will recognise the drive. The back ups i am creating seem to be burning ok.
When i have tried the discs in my ps2 (version 4, with magic 3 installed) the screen would either go to the dvd options or to the 'incorrect disc' screen.
the cd-r's i have backed up are working fine, as are the originals (ps1 and ps2 games), i have also cleaned the lazer.
The media i have used. Verbatim datalifeplus, Datasafe (unbranded) and Mirror( £3 each !).
Is it possible that there could be an error with my install of the magic 3, which would effect the loading of ps2 back ups while the ps1 back ups are ok, or is it the media i am using, or my computer ( 733mhz,128ram,6 gig spare), or or or