Microsoft.MetadirectoryServices.AttributeNotPresentException: Attribute "blah" is not present.

Hi,

I am trying to write a custom extension in Visual Basic that creates Exchange mail-enabled users (MEUs) in my target directory, for each mailbox in my source directory. I have the code below in my source MA extension, and have specified "targetAddress" as the flow rule name under the advanced attribute flow on the source MA. However, when I run a sync on the source MA, it returns the error "Microsoft.MetadirectoryServices.AttributeNotPresentException: Attribute "targetAddress" is not present."

Any idea what I could be doing wrong?

Thanks in advance,

Adam

 Case "targetAddress"
                If csentry("targetAddress").IsPresent Then
                    mventry("targetAddress").Value = csentry("targetAddress").Value
                Else
                    mventry("targetAddress").Value = ("SMTP:" & csentry("mailNickname").Value & "@contoso.com")
                End If