Have you tried to just add the attachment rather then creating the attachment object:

lcFullPathForClaimAttachment = SYS(5) + SYS(2003) + "\" + This.cClaimFileName
myItem.Attachments.Add (lcFullPathForClaimAttachment)

The add method will create a new attachment object if it needs to.
Look at the Count method to see if the attachment has been added eg. myItem.Attachments.Count.


Paul.