exim and cyrus

I don't know, what exim and cyrus are donig. 

I fetch my mail with fetchmail. That works fine. Exim can deliver the mail to 
the local mailfolder. I can read them with mutt on the server!!!!!

imapd is running on the machine. I can access to the users mailbox peter from 
a remote machine. I can put new mails into the folder or mkdir. 

So cyrus seems to work.

I think there is a problem between exim and cyrus.

This is the part of my exim.conf, which works fine for the local mailbox

#################

local_delivery:
  driver = appendfile
  group = mail
  mode = 0660
  mode_fail_narrower = false
  envelope_to_add = true
  return_path_add = true
  file = /var/spool/mail/${local_part}

############

When I comment these lines and write instead this:

###########

local_delivery:
  driver = pipe
  command = "/usr/sbin/cyrdeliver -m peter peter"
  return_path_add = true
  return_output = true
  prefix = ""
  user = cyrus

############

mails are not delivered the the mailbox peter.

Why not?

This is a part of my exim log:

#############

2003-01-30 13:42:12 18eE1E-0006K6-00 <= r1e2t3e4p3@xxxxxx H=localhost 
[127.0.0.1] P=esmtp S=1198 id=200301301342.07416.r1e2t3e4p3@xxxxxx

2003-01-30 13:42:12 18eE1E-0006K6-00 => peter <peter@localhost> D=localuser 
T=local_delivery

2003-01-30 13:42:12 18eE1E-0006K6-00 Completed

############################

Seems to be ok.

In cyrus mail.err are no entries at this time and no entries, which could be 
affected by the delivery from exim. 

My question is now, is there any logfile for the delivery from cyrus?

What could be wrong? Where is my mistake?

Thank you for your answer!!!!!

Greetings Peter