install cd won't boot

I've been trying to make a boot CD from the 9/6/2014 iso.  I tried more 
than than one iso, from different mirrors, using different computers, 
and different programs.  The result was always something about block 0 
is not a valid boot block.
So, I tried isomarkboot from Gentoo.  No luck.
Then I booted an old Debian (5.0 lenny) installation and used their 
isomarkboot.  I just entered isomarkboot file.iso boot/bootlx.  This 
time, it did start to boot.  It died with kernel stack not valid and 
three chevrons.
I'm out of CD-Rs.

I always figured it was my terrible IDE chip.  However, I have a Gentoo 
CD I marked 5/5/2013 that boots perfectly.  So, I have to conclude that 
my hardware can function.
I don't imagine that the aboot package has changed recently.  I don't 
know.  My hard drives are SCSI and aboot works for them.  I never tried 
isomarkboot before.
I left out any initrd parameters when I tried the Debian isomarkboot. 
There are initrd parameters passed to the kernels in the aboot.conf file 
on the CD, but I don't know what isomarkboot needs.

I assume the boot CD kernels work.
The man page says I can use a loop device or an image file.  The 
question is:
What is the proper syntax for running isomarkboot to make a Gentoo 
install CD?  Anything tricky?

Note: I ran the sha512sum on one iso file and eyballed the result.  It 
was right.
The next iso will probably be out soon.  My spindle of CD-Rs should 
arrive soon too, ha ha.  I'll keep trying.

Adios,  DW