Samba HOWTO Collection November 14, 2003 I have searched for usrmgr, usrmgr.exe, manager, user manager throught the Samba HOWTO Collection and it looks like there is no informatio under which circumstances should the USRMGR.EXE administration (Domain User Manager aka User Manager for Domanins from Windows NT4.0, see http://support.microsoft.com/default.aspx?scid=kb;en-us;173673) should work.
This is IMHO beyond the scope of the document. USRMGR.exe is a 3rd party tool to administrate users in a domain. So when Samba is operating in domain mode (as DC), it'll work.