[horde] Trouble with sending mail

[Ben Green]

I have a strange problem sending mail, linked to the Horde_mail  
version. Basically the headers are not separate from the body, the  
body of the mail appears inside the mail, like this botton part of my  
mail:

Date: Sat, 17 Mar 2012 11:08:54 +0000
Message-Id: <E1S8rVG-0003c6-0x at mailserv.psand.net>
Received: from cpc10-aztw24-2-0-cust114.aztw.cable.virginmedia.com
      (cpc10-aztw24-2-0-cust114.aztw.cable.virginmedia.com [82.45.35.115]) by
      slackmail.co.uk (Horde Framework) with HTTP; Sat, 17 Mar 2012  
11:08:53 +0000
      Date: Sat, 17 Mar 2012 11:08:53 +0000
      Message-ID:  
<20120317110853.Horde.bhzyWWOelG9PZHDF8uVRJ7A at slackmail.co.uk>
      From: Ben Green <ben at example.net>
      To: "bengreen at otherexample.net" <bengreen at otherexample.net>
      Subject: this is the subject of the message
      User-Agent: Internet Messaging Program (IMP) H4 (5.0.19)
      Content-Type: text/plain; charset=ISO-8859-1; format=flowed; DelSp=Yes
      MIME-Version: 1.0
      Content-Disposition: inline
      This is the body of the message, and my signature.
      ==
      From Ben Green
From: www-data <ben at example.net>

anyone any ideas? How do I debug this? Another issue is that www-data  
appears to have sent the message, which is not correct. I've submitted  
a bug with details of library versions and the full mail headers:

http://bugs.horde.org/ticket/11081

Cheers,
==
 From Ben Green