[imp] Ingo backend troubles

[Earnie Boyd]

I am now trying to setup Ingo filtering with IMAP client side
filtering.  I have the backends array defined as

$backends['imap'] = array(
    'driver' => 'null',
    'preferred' => $_SERVER['HTTP_HOST'],
    'hordeauth' => true,
    'params' => array(),
    'script' => 'imap',
    'scriptparams' => array()
);

but I am get ``Unable to load the definition of Ingo_Script_.''
error.  The horde.log has

Sep 12 17:55:00 HORDE [emergency] [ingo] Unable to load the
definition of Ingo_Script_. [on line 116 of
"/usr/local/phplib/horde-3.0.5/ingo/lib/Script.php"]

The versions are:
horde-3.0.5
imp-h3-4.0.3
ingo-h3-1.0.1
kronolith-h3-2.0.3
nag-h3-2.0.2
turba-h3-2.0.3

TIA,
Earnie