How to get ADSI Err.Description ???

I have ASP page on W2K SP4 server.

I have the following excerpt of code:

On Error resume next

Set myObj = GetObject ( DN)

ErrNo = Err.number
ErrTxt = Err.Description

Err.Clear

On Error goto 0

If ErrNo <> 0 Then

Here my error processing code.
I have here ErrNo = 0x80072030, with means that ldap object not found,
but ErrTxt is blank.

End If

How can I have Err.Description filled. Because there are some errors which
are part of the normal processing flow and I dont care of Err.Description,
but other errors are "abnormal" and I want to show them to the user with
some meaning.

Thanks for help.
François.