mod_radius error

[Oguzhan Kayhan]

Hello
I am trying to use mod_radius on ubuntu.
But i am getting error:

Invalid command 'AddModule', perhaps misspelled or defined by a module not
included in the server configuration.

When i comment out the line with AddModule from httpd.conf i got the
following error message.


Invalid command 'AuthAuthoritative', perhaps misspelled or defined by a
module not included in the server configuration.

These are the enabled modules on apache
alias.conf       authn_file.load       authz_host.load  cgi.load 
mime.conf         php5.conf      ssl.conf
alias.load       auth_radius.load      authz_user.load  dir.conf 
mime.load         php5.load      ssl.load
auth_basic.load  authz_default.load    autoindex.conf   dir.load 
negotiation.conf  setenvif.conf  status.conf
auth_mysql.load  authz_groupfile.load  autoindex.load   env.load 
negotiation.load  setenvif.load  status.load

And this is my apache version.
Server version: Apache/2.2.8 (Ubuntu)
Server built:   Jun 25 2008 13:54:13