Apache configuration for using plugin Xsendfile

I am facing some problem in using the plugin Xsendfile(http://
john.guen.in/rdoc/x_send_file/).Here in README for setting up web
server , the author has given a link to

.But when I try to Install mod_xsend_file.c
I am getting an error
apxs:Error: Activation failed for custom /etc/apache2/httpd.conf
apxs:Error: At least one `LoadModule’ directive already has to exist…
I tried to load this module manually from /etc/apache2/apache.conf but
apache2 fails to restart .Kindly suggest a way to make this plugin
work.Basically to include this module on apache2.
I am using RAILS 1.2.3 and Apache/2.2.8 (Ubuntu).

Thanks in advance