HordeSession class won't create, plz help

[alexus]

in my horde/test.php3 ( http://box.nexgen.com/horde/test.php3 )
I'm geting

View phpinfo() screen
Horde Versions
  a.. Horde: 1.2.4
  b.. IMP: 2.2.4
PHP Version
  a.. PHP Version: 4.0.5
  b.. PHP Major Version: 4
  c.. PHP Minor Version: 5
  d.. PHP Version Classification: release
  e.. You are running a supported release of PHP4. Enjoy the ride!
PHP Module Capabilities
  a.. IMAP Support: Yes
  b.. LDAP Support: Yes
  c.. MySQL Support: Yes
  d.. PostgreSQL Support: No
PHPLIB Configuration
  a.. track_vars: Yes
  b.. PHPLIB (is page_open() defined): Yes
  c.. I am now going to try to create a HordeSession class. If this line is
the last thing that you see, then you do not have class HordeSession defined
in the phplib local.inc file. Fix that before proceeding.
what am i missing? what hordesession class is it talking about?