RedHat 7.0 release 2.2.17-3 for Alpha. After adding a user and password in Linuxconf, the message "Error message from remadmin:** warning **: Unknown type for widget "tree-0.book.main-1- 3.cl." opens in the Terminal Window where linuxconf was launched. The user and password is added correctly. This does not happen when adding a user and a password using RedHat 6.2 for Alpha.
Believe this is fixed in the current release