errors attaching file to email

[bob.reven@unix1.trinity.ox.ac.uk]

i used to have horde 1.2.3 and imp 2.2.3 with Mysql 3.22.32 installed by
RPM on an redhat 6.2 intel linux system. it all worked fine but there was 
the bug with IE 5.5 so i did an RPM upgrade to IMP 2.2.4 and horde 1.2.4
and now whenever i attach a file i get an error. i browse the file okay but when
i click on "attach" the browser returns the errors detailed below. 

the wierd thing is that the file does get attached and the recipient gets the
mail complete with attachment just fine. the errors are however a little
disconcerting to users so if anyone has seen this or can suggest what 
could be wrong i would appreciate any advice. 

also does anyone know when IMP 2.3 will be officially released?

sincerely,

bob reven

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Warning: File Upload Mime headers garbled [ in /home/httpd/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
Composing: Added an attachment... - Wed 14 Mar 2001 08:48:44 AM GMT