Same happens here with a bad burn I had (where it couldn´t even verify, or deny access to the medium and "Disc Read Error"/DRE showed-up, after some time).
When I try to play this, it appears that my PS2 cannot load the disc - fast, sort of clicking noise and I can hear the DVD spinning up and down, up and down...
Another thing which comes to my mind, but your version shouldn´t have problems with it.
Now DVD5 backups are just fine so I don't think it is a laser problem (or it possibly might be, don't know, that's why I ask). I have PS2 50004 series.
Thanks for any possible comments.