I was able to boot the iso-cd after several time of tricky pressing the ctrl-key: Just press the ctrl or maybe other key erlier b4 "the promt for entering any key to boot from CDROM" appear!
But it is not clean solution, not granted that it will work by u. Wut I actually gonna say is that I prefer to assume that problem to be the problem of the old CD-READER/WRITER or maybe even the media itself rather than the way how u burnt the CD.
I've several miraculous experience with those booting of those burnt CD. I think old CD-READER/WRITER could have problem with booting those burnt CD because 1st the optic head is maybe already not so clean, 2nd the CD-R/CD-RW reflection of optic signal is not that good, so that in case when it reads in normal operation it had the chance to re-read the unsuccesfully read data, but during the booting process it has not that chance or not enough ..
my old CDRW is an creative RW8433E
I'd several time bad exerience of booting linux-iso or other burnt CD (mostly with CD-media with blue background), but when I replace another CD-READER(pioneer) it boots smoothly ..
It seemed to have no problem to boot from recorded CD with silver or gold background. Therefore I said the media played also a role for the booting problem ..
Hope that clear any of ur question ..