I've downloaded the Parted Magic.iso liveCD and extracted the content with IsoMaster. Aftre that I've added some packages to the folder where I've extracted the Parted Magic folder and file. I intended to create a hybrid bootable repository.
I've issued the following command into that directory:

mkisofs -o Something.iso -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -J -R -iso-level 2 ./

I've burned the created ISO. It boots, gparted starts but somehow the process of shrinking the ext3 partition fails with messages "short read...."

Could the command above damage the original image, or something else went wrong?