[horde] Fatal error: Undefined class name 'horde' in config/conf.php on line 45

[Kamanhalli, Pavan S]

Hi All,
        I am getting error of this kind "Fatal error: Undefined class
name 'horde' in config/conf.php on line 45". The 45th line in that
conf.php contains, 

                    $conf['cache']['params']['dir'] =
Horde::getTempDir();

  Does anyone know the solution?

Thanks,
 Pavan