Fwd: Returned mail: unknown mailer error 2

Hi,
I have recently had several web page requests
returned, as per the example below.
Can you advise what I am doing wrong ?
Many thanks
Nigel
--- Mail Delivery Subsystem
<MAILER-DAEMON@kabissa.org> wrote: > Date: Tue, 3 Apr
2001 03:47:23 GMT
> From: Mail Delivery Subsystem
> <MAILER-DAEMON@kabissa.org>
> To: <nigel_heasman@yahoo.co.uk>
> Subject: Returned mail: unknown mailer error 2
> 
> The original message was received at Tue, 3 Apr 2001
> 03:47:23 GMT
> from web11403.mail.yahoo.com [216.136.131.233]
> 
>    ----- The following addresses had permanent fatal
> errors -----
> "|/usr/home/www4mail/bin/www4mail
> /usr/home/www4mail/conf/www4mail.cfg"
>     (expanded from: <www4mail@kabissa.org>)
> 
>    ----- Transcript of session follows -----
> sh: /usr/home/www4mail/bin/www4mail: not found
> 554 "|/usr/home/www4mail/bin/www4mail
> /usr/home/www4mail/conf/www4mail.cfg"... unknown
> mailer error 2
> 

> ATTACHMENT part 2 message/delivery-status 


> ATTACHMENT part 3 message/rfc822 
> Date: Tue, 3 Apr 2001 12:45:36 +0100 (BST)
> From: nigel heasman <nigel_heasman@yahoo.co.uk>
> To: www4mail@kabissa.org
> 
> http://www.kabissa.org
> 
> =====
> Greetings from Yahoo mail
> 
>
____________________________________________________________
> Do You Yahoo!?
> Get your free @yahoo.co.uk address at
> http://mail.yahoo.co.uk
> or your free @yahoo.ie address at
> http://mail.yahoo.ie
> 


=====
Greetings from Yahoo mail

____________________________________________________________
Do You Yahoo!?
Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk
or your free @yahoo.ie address at http://mail.yahoo.ie

Received on Tuesday, 3 April 2001 07:51:53 UTC