you said you donwload the bwa file. I would suggest that you make the bwa files for each individual cd. I reccomend this as someone who doesn't know if all cds are protected or not. So you might try that.
If that doesn't work, i would try changing the sector stepping size. I don't remember the ones that seem to work, but i believe the guide you mentioned says.
Finally, if that doesn't help you, it is possible that your laptops cd drive is just not compatible. For example, in my system, neither my toshiba dvd/cd-rw drive or yamaha cdrw will work when running backups of securom 4.8.xx. Only my liteon 52x cd-rw. The cds youve burned that you believe ot be coasters, have you only tried them in your laptop and main system? I would try them in as many systems as possible before pitching them. Hope that will help you to accomplish a working backup.
One more thing, when making your bwa files, different drives have a better ability to make them. My liteon made a horrible bwa file for vice city. But my toshiba dvd/cd-rw made a perfect one. You want to try to have a nice smooth curve, if there is only one or two spikes it will probably still be usable, but any more than that and your chances of the backup working are slimmer. And when making the bwa, for me, the first 50,000 sectors were all that were needed and that is also reccomended by blackcheck, the author of twinpeaks.