Login problem 4.0

[Merphis Ellis <sysop jupiter athensnet com>]

I am tring to setup a system, I am using the redhat 4.0 disk and appling
the updates as called for on redhat's web page. 

After I do this I can no-longer log in. 

At the prompt I type a user name and passwd, I get 4 bad login message
and the system returns to the prompt.

This has become old as I have 6 systems and they are one by one going
this way

Please help

Merph