Attachment displayed as code

I've got a strange problem when receiving a mail from a specific
customer. The attachment is displayed as a code. The client version I
use is groupwise 6.5.7. Al other mail is working fine and attachment
are displayed normal.

Has anyone a solution for this?

The specific mail lookes like this:


MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="----_=_NextPart_000_000099E7.01BE9EAC"

This is a multi-part message in MIME format.

------_=_NextPart_000_000099E7.01BE9EAC
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

<<>>

------_=_NextPart_000_000099E7.01BE9EAC
Content-Type: application/octet-stream;
name="filename.slr"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
filename="filename.slr"

UEsDBBQAAAAIAA04bTd/
fyIGrgUAANwZAAAMAHEAUzExMTMwMTAuaWNmU0RcAIgAAAAACA BML9LM
Y2RgaRFhYGBQYYAAAyBmZAIzWRWAhAKQzcgI4QsBCSaGCAZmEE 9AheE/
ozwDIytEThRI2D7m8L16

<<>>

------_=_NextPart_000_000099E7.01BE9EAC--