It’s not possibel to create a botdisk using Avast.

Like Culpeper said it uses to own process called : VRDB

If you really want to create a good boot disk go here :

http://www.bootdisk.com/

You can also download “F-prot AV for dos” if you ever feel the need to scan in dos. (if you get infected and can’t boot). get it here :

http://www.wowwebdesigns.com/tools/id_5/

Waldo