Forgot to provide these details as they may be important:

The size of the knx/source/KNOPPIX dir/files is 1.8GB. The personal files I'm attempting to add to it by placing in knx/source/KNOPPIX/var/www/myDirectory are 1.3GB for a total of 3.1GB. Previous remastering attempts resulted in an iso image that was ~2GB. Again, when I added more files recently they were very small so the resulting image (should the remastering work) would most certainly be < 2.1GB.

Again, need help figuring out why I can no longer create the sio image. Is it perhaps a limitation of mkisofs?

Regards, John