MIME Outlook format problem

Please i need your help.
This is a format in which we always receive mail(s) from this client of ours and management wants it resolve. I know, from what I can infer that the sender sends using MIME format but don’t know what’s is wrong that we couldn’t receive it normally.
Below is a sample.

MIME-Version: 1.0
Content-Type: multipart/alternative;
boundary=”—-=_NextPart_000_002A_01C43F16.6A5B1140″
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 5.00.2919.6600
X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6600
X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on abalone.mweb.co.za
X-Spam-Level:
X-Spam-Status: No, hits=0.3 required=7.5