Jammer,
Sorry, I don't have a SCO box to play with so it took a while.
Found the following at
http://pcunix.com/SCOFAQ/scotec2.html#disabled
When a user tries to log in, they get "Account is disabled -- see Account Administrator"
The account has been locked.
As root, run
passwd -u username
You can lock an account with "passwd -l".
Locking and unlocking can also be done through the Scoadmin Account Manager under "Login Controls".