I found a public download:
http://melrom.com/files/dlgmaker.zip
Extract the exe out of the zip, put a blank floppy in your drive, and run the exe. This MUST be done on a Win95/98/ME machine, it will NOT work on a 2K/XP machine. It will make a bootable floppy, you need to boot with it and run the diagnostics. Once the floppy is made, it doesn't matter what OS is on the machine that has the drive which you are testing.