if you've made the images with clone that could be the problem, clone is useless for ps2 games use cdrwin or discjuggler.
what file extensions are the files you are trying to burn?
have you installed discjuggler4 recently? (if so then delete and reinstall nero to put the aspi drivers back correctly)
i had a similir problem on my plex (16x)about 4 weeks ago, started to get lights flashing then it just died, so i replaced it. i have to also ask what speed media are you using? because i get similir problems on 32x media when burning on my 48x drive if i dont use 48x media