attachment with imp

[edward@ita.org.mo]

Dear All,

When I post a E-mail to a user ( test the imp ) with a attached file ,
these is the error result :

Warning: File Upload Mime headers garbled [ or in
/home/webmaster/html/horde/imp/compose.php3 on line 1

Warning: Cannot add more header information - the header was already
sent (header information may be added only before any output is
generated from the script - check for text or whitespace outside PHP
tags, or calls to functions that output text) in session.inc on line 448

Warning: Cannot add more header information - the header was already
sent (header information may be added only before any output is
generated from the script - check for text or whitespace outside PHP
tags, or calls to functions that output text) in session.inc on line 449

Warning: Cannot add more header information - the header was already
sent (header information may be added only before any output is
generated from the script - check for text or whitespace outside PHP
tags, or calls to functions that output text) in session.inc on line 450

Warning: Cannot add more header information - the header was already
sent (header information may be added only before any output is
generated from the script - check for text or whitespace outside PHP
tags, or calls to functions that output text) in ./templates/doctype.inc

on line 8

So, can you help me ?
Thanks,

Sorry, I can't post the compose.php3 , session.inc and doctype.inc in
here...

Edward.