MEPIS 3.43 will not add a new user

I have a problem adding new user accounts in MEPIS version 3.43. Please note that for my current MEPIS installation, I have not tried to add users before. However, in previous MEPIS 3.43 installations (on same pc, etc) everything went fine.

Here are the steps:

1) First, I log in using my regular (1 and only regular account) MEPIS 3.43 account. I click on the lower left icon to go to the "MEPIS Config (OS Center)" and enter my root password to proceed. Then, I go to "add user" and type in a name and password for that new user I want to add. Unfortunately, no matter what name / password I type, I get the same reply: failed to add new user. I log off.

2) Second, I log in as "root" at the login screen instead of my regular account. I click on the lower left icon go go to the "MEPIS Config (OS Center)" then I go to "add user" and type in a name and password for that new user I want to add. It works fine. I log off.

3) Third, I log in again as my 1st regular account (the account I used in step 1). I try to add another account that way, so I click on the lower left icon to go to the "MEPIS Config (OS Center" and enter my root password to proceed. Then, I go to "add user" and type in a name and password for that new user I want to add. Again, no matter what name / password I type, I get the same reply: failed to add new user. I do not log off.

4) Fourth, out of curiosity, I remain logged in my regular account at the MEPIS Config and try to delete the new user account I just created in step 2. I deleted it fine.

So, when using my regular account, why am I unable to add a new user, but able to delete the new user? Of course, how can I fix this? I do not want to login as "root" at the login screen everytime I want to add a new user. Please note, I have never had this problem before with MEPIS 3.43. I'm lost. Any thoughts?