The reason for this problem is that WA now checks attachments for viruses before letting users download them and infect their computer. This is done by decoding the attachment from base64 and asking LISTSERV to scan it for viruses. In the 1.8e release code, this was incorrectly done in such a way that you had to log in if you were not already logged in. In the upcoming level set, this is no longer the case. You should be able to get a fix now from support if you are in a hurry - the fix was written a long time ago.

  Eric