I. too, have this exact problem under different circumstances. My circumstances has involved several differing attempts to produce a LiveDVD by updating the booted LiveDVD at the end of a desktop session following procedures and steps I have found on the Puppy Sites. They have involve placing SFS files on the DVD and updating the BOOTCONFIG file using the Puppy provided utilities., then saving the session changes on reboot. All cases, whether manual, or using the BOOTMANAGER Bootup Configuration utility ends with this exact error. My only circumvention to get a FATDOG64 desktop session is to reboot the LiveDVD with puppy pfix=1 to get my desktop session. And this reboot does NOT have the SFS changes I was looking to have.kirk,
I made another sfs/iso/CD without devx but with 8 additional sfs files included:
audio-all-in-one-amd64-7.sfs
fd64-32bit-libs.sfs
hugin-2010.0.0-amd64.sfs
jre160_amd64-3.sfs
skype_static-2.1.0.81.sfs
wine-1.2-rc5-i486-4.sfs
xcas-0.8.6-amd64.sfs
go-oo_32_amd64-3.sfs
Following your procedure a new sfs file of 560 MB was created and a new Fatdog64-500-extra.iso as well. burniso2cd was used to burn the iso and the system was rebooted using the new CD.
The same problem happened while booting the CD after the sfs was copied to RAM as detailed below.
BUT copying the new sfs file to a pen drive allowed the CD boot to boot successfully ( it found the sfs file on the pen drive and used it ) and all ran very well.
Also, booting via grub in the MBR of a pen drive with the sfs and other files copied to the pen drive booted nicely as well.
SO, as far as I can tell it is a size issue while booting solely from the CD. I was concerned that it might have been a devx associated problem, but now it seems not so.
ERRORS REPORTED:
Loading 'fd64-500.sfs' main file ... copying to ram done
Dumping last lines of /tmp/bootinit.log ...
mount: /dev/sr0 is write-protected, mounting read-only
writing '/mnt/tmpfs/fd64-500.sfs': No space left on device
mount: mounting /dev/loop0 on /pup_ro2 failed
mount: mounting unionfs on /pup_new failed
Dumping last lines of kernel log ...
<7> ISO 9660 Extensions: RRIP_1991A
<7> ISO 9660 Extensions: Microsoft Joliet Level 3
<7> ISO 9660 Extensions: RRID_1991A
<3> aufs test_add:226:mount[1743]: unsupported filesystem, /pup_ro2 (rootfs)
I am certain that there is either a lack of understanding on extending a LiveDVD or there is sort of a problem wtih what FATDOG64 was expecting at boot time as it tries to incorporate the additional SFS files.
Anyone with any ideas on where to look for resolution. Be aware that what I hit and what @fatdog64kudos hit, I believe are related.