Christian,

Not sure why the problems with the .Put style... seems to work well for WSH and works for "some" properties using KiXtart, but not all of them. However doing it this way seems to work quite well for me using KiXtart v4.10
Please give it a try and let us know how it goes. The .SetInfo on the end only verifies the last entry was updated correctly. You would need to put that same code after each update command in order to see the error code for each command.

code:
Break On
$adsUser = GetObject("LDAP://cn=einhirn,ou=someou,ou=myusers,dc=rz,dc=mydomain,dc=de")
if @ERROR<>0
	? @SERROR + " (" + @ERROR + ")"
	Quit 1
endif

? $adsUser.sAMAccountname
? $adsUser.AccountDisabled 
? $adsUser.IsAccountLocked 
? $adsUser.PasswordRequired 
? $adsUser.FirstName 
? $adsUser.LastName 
? $adsUser.DisplayName 
? $adsUser.LoginScript 
? $adsUser.Profile 
? $adsUser.HomeDirectory 
? $adsUser.HomeDrive
? $adsUser.Title
? $adsUser.EmailAddress

$adsUser.sAMAccountname = "EgonBeer"
$adsUser.givenName = "Egon"
$adsUser.sn = "Bottlebeer"
$adsUser.DisplayName = "Egon Bottlebeer"
$adsUser.Profile = "\\bigserver\homedir\profile"
$adsUser.loginscript = "kix32 login.kix"
$adsUser.HomeDirectory = "\\bigserver\homedir"
$adsUser.Put ("homeDrive", "p:")
$adsUser.title = "Finance Dept Manager"
$adsUser.userPrincipalName = "Egon.Bottlebeer"
$adsUser.telephoneNumber = "(213) 777 8888"
$adsUser.EmailAddress = "egon.beer@@mycompany.com"
$adsUser.SetInfo
? "SetInfo errorlevel is:"+@error+" "+@Serror
$adsUser = ""