[imp] imp fatal error

[Vikram]

After configuring Horde and IMP 3.2.1 I was able to login at this page
without any errors: http://mail.example.com/horde/imp/test.php

But when I proceeded to http://mail.example.com/horde/imp/index.php, I get
following error:

Fatal error: Failed opening required
'/var/www/html/mail/horde/imp/redirect.php'
(include_path='.:/usr/share/pear') in /var/www/html/mail/horde/imp/index.php
on line 25


What is wrong?  Please advise.  Thanks a lot.

Greetings,
Vikram