[horde] horde installation problem

[zafar]

hello sir
 i found that error after renaming the configuration files.
but no screen will be display,only display a blank error page.
but when i test the test page it give me that errors.
so plz tell me what things are required must....and which are not necessar.
thanks
Horde Versions
  a.. Horde: 2.1
PHP Version
  a.. View phpinfo() screen
  b.. PHP Version: 4.0.6
  c.. PHP Major Version: 4.0
  d.. PHP Minor Version: 6
  e.. PHP Version Classification: release
  f.. This version of PHP is not supported. You need to upgrade to a more
recent version.
  g.. Horde requires PHP 4.1.0.
PHP Module Capabilities
  a.. FTP Support: Yes
  b.. Gettext Support: Yes
  c.. IMAP Support: Yes
  d.. LDAP Support: No
  e.. MCAL Support: No
  f.. Mcrypt Support: No
  g.. MySQL Support: Yes
  h.. PostgreSQL Support: Yes
  i.. XML Support: Yes
Miscellaneous PHP Settings
  a.. short_open_tag enabled: Yes
  b.. magic_quotes_runtime set to Off: Yes
  c.. file_uploads enabled: Yes
PHP Sessions
  a.. Session counter: 1
  b.. To unregister the session: click here
PEAR
  a.. PEAR - Yes
  b.. Recent PEAR - No
  c.. This version of PEAR is not recent enough. See the Horde PEAR page for
details.
  d.. Mail::RFC822 - Yes
  e.. Log - Yes
  f.. DB - Yes