The way ahead is definitely trying to calibrate the laser, have a look at this site.
http://www.ps2.nu/playstation-2-laser-calibration.htm
Although it recommends that you don't calibrate the laser without a scope I managed to do it no problem. All you have to do is make a mark where the pot that you adjust is to start with and then turn it up about one sixteenth of a turn and try it again with dvdr. If still not work turn up a sixteenth again. I had a version four that wouldn't read dvdr games or movies and used to come up with the same error message as yours and got it to read them no problems doing this. As yours won't read cdr's either once you've got the dvdr's reading you'll then have to adjust the cd pot as well but do this in the same way and take your time about it and you'll have no problems. It might also save you having to buy a new PS2.
Let us know how you get on......Regards and happy Xmas......
