Checks the username and password against NT Authentication.

Note that unlike the Authenticate this method does not set the oUser member object - this method simply returns success or failure.

Syntax:	o.AuthenticateNT(lcUsername, lcPassword, lcDomain, lnFlags)
Return:	.T. or .F. See cErrorMsg on failure.
Parameters:	lcUsername User name to authenticate lcPassword Password for the user. lcDomain Optional - domain name lnFlags Optional - Logon flags