Fatal error in imp

[fabrizio]

Hello all I've Installed Imp on a Linux Slackware7.1.
 This is the output of the Horde test.php3 :
 
 Horde Versions
 Horde: 1.2.7 
 IMP: 3.0
 
 PHP Version
 
      PHP Version: 4.1.1 
      PHP Major Version: 4 
      PHP Minor Version: 1 
      PHP Version Classification: release 
      You are running a version of PHP4 older than 4.0.3. You need to
 upgrade to at least 4.0.3. 
 
 PHP Module Capabilities
 
      IMAP Support: Yes 
      LDAP Support: No 
      MySQL Support: Yes 
      PostgreSQL Support: No 
 
 PHPLIB Configuration
 
      track_vars: Yes 
      PHPLIB (is page_open() defined): No 
 
 Miscellaneous PHP Settings
 
      register_globals set to On: Yes 
      magic_quotes_gpc set to Off: No 
      magic_quotes_gpc causes data coming from GET, POST, or COOKIE modes
to
 be processed so that single quotes and
      backslashes are prefixed with a backslash (\'). This makes your email
 look very ugly. Turn it off. If the PHPLIB installation
      instructions claim that they want this setting on, they lie - PHPLIB
 versions 7 and later work perfectly well with it off. 
      magic_quotes_runtime set to Off: Yes 
  
 
 The smtp server is qmail
 The imap server is Courier imap 1.43
 
 When I point my browser on the imp page (http://127.0.0.1/horde/imp)
 I get this error:
 
 Fatal error: Failed opening required
 '/var/lib/apache/htdocs/horde/imp/lib/../../lib/Browser.php'
 (include_path='.:/usr/local/lib/php') in
 /var/lib/apache/htdocs/horde/imp/lib/base.php on line 18
 
 Ups!!! any help?