To make a DOS boot disk you need to be operating in a DOS! This can be done from booting up with a DOS Boot disk or from a DOS operating system.

To create the diskett use the following command.
Format a:/a/s

The disk should have:
IBMBIO.com
IBMDOS.com

Other files that can be included incude:
Autoexec.ba
config.sys
command.com

Or you can simply visit a web site such as www.bootdisk.com and download one. To use the boot disk on the CD simply copy the contents of the boot disk folder to a floppy. Or unzip the following link to a floppy.
DOS boot disk