[imp] unable to send data

[Peter Hellman]

I have installed imp 3.2.1, horde 2.2.1.
This is not my firtst time installing imp. (Which may have caused me to 
hurry a bit too much)

When sending mail I get "unable to send data", and the following log entry :
HORDE [error] [imp] unable to send data [on line 918 of 
"/home/webmail/horde/imp/compose.php"]

IMP sends EHLO, MAIL FROM, RCPT TO: after OK on RCPT TO: IMP sends QUIT.

My server setting :
$servers['imap'] = array(
     'name' => 'Default Server',
     'server' => '<fqdn of server>',
     'protocol' => 'imap/notls',
     'port' => 143,
     'folders' => '',
     'namespace' => 'INBOX.',
     'maildomain' => '',
     'smtphost' => '<fqdn of smtp server, same as name atm>',
     'realm' => '',
     'preferred' => ''
);

Downloading attachment doesn't work either, no error log, request goes 
from browser, but noting happens.
test.php :

Horde Versions

     * Horde: 2.2.1
     * IMP: 3.2.1 (run IMP tests)

PHP Version

     * View phpinfo() screen
     * PHP Version: 4.1.2
     * PHP Major Version: 4.1
     * PHP Minor Version: 2
     * PHP Version Classification: release
     * You are running a supported version of PHP.

PHP Module Capabilities

     * DOM XML Support: Yes
     * Gettext Support: Yes
     * IMAP Support: Yes
     * LDAP Support: No
     * MCAL Support: Yes
     * Mcrypt Support: Yes
     * MySQL Support: Yes
     * PostgreSQL Support: No
     * XML Support: Yes

Miscellaneous PHP Settings

     * magic_quotes_runtime disabled: Yes
     * file_uploads enabled: Yes
     * safe_mode disabled: Yes
     * trans_sid disabled: Yes

PHP Sessions

     * Session counter: 4
     * To unregister the session: click here

PEAR

     * PEAR - Yes
     * Recent PEAR - Yes
     * Mail - Yes
     * Mail_Mime - Yes
     * Log - Yes
     * DB - Yes
     * Net_Socket - Yes
     * Date - Yes
     * HTML_Common/HTML_Select - Yes

Thank you and have a nice day
//Peter Hellman