I am running Windows have the same error as you, but I am not very good in DOS.
Did you manage to resolve the problem and get to your desktop in safe mode?
I am running ME on a e-machines 633.
Was installing a DSL modem and had to reboot after resetting my ethernet card to get a DHCP address.
When the machine rebooted, it came up with the error
Cmdninst has caused an error in <unknown>
Cmdninst will now close.
I get this error even when I try to start up in safe mode. I can never get to the desktop. I have a CD that will allow me to boot to DOS (it says that it's version of ME is expired), and I can do most things a person can do in DOS (trying to remember the commands is the hard part) but what can I do in DOS to fix this?
From the research I have done, it appears that this error comes up because of a bad device driver. I look for *.drv files, but none appear to have any relation to the DSL modem (Actiontec) that I was installing.
Any ideas or guidance would be much appreciated.