While installing RedHat 6.0 on an i386 platform, when I entered the root password on the next screen I had the message ERROR "echo [root password]" where [root password] was indeed the root password I had just entered. I do have a ";" (semi-colon) as one character of the password, so I suspect a script confused that for an end of a command. The installation was based on the 6.0 release dated 4-19-1999
I was unable to replicate this problem using the final release of Red Hat 6.0. I included a semi-colon in the password as instructed. It was written to the disk correctly and was verified to work upon reboot.