Hi Terry,
There's no writefs command, the good command is :

tazusb writefs

wich create a new rootfs with the system tree (exlude the home tree)

There's also a new command wich is :

tazlito writeiso

This one create a new rootfs including you're home tree (the users config etc). I never have try this one, so I can't tell more about it.

I you want more info, you can type :

tazusb --usage

and

tazlito --usage

You can find some infos and exemples in the slitaz documentation and in the wiki.