Balancermember Can't find 'byrequests' lb method

I am using apache 2.2.8 for my debian ubuntu, while configuring apacehe with proxy balancer.I faced the problem "BalancerMember Can't find 'byrequest lb method'".

sudo /etc/init.d/apache2 restart
* Forcing reload of web server (apache2)...
Syntax error on line 673 of /etc/apache2/apache2.conf:
BalancerMember Can't find 'byrequests' lb method
...fail!
## Apache file (from error line)

BalancerMember http://127.0.0.1:8000
BalancerMember http://127.0.0.1:8001


ServerName data_seed
DocumentRoot /var/www/ruby/public

Options FollowSymLinks
AllowOverride None
Order allow,deny
Allow from all

RewriteEngine On
RewriteCond %{DOCUMENT_ROOT}/system/maintenance.html -f
RewriteCond %{SCRIPT_FILENAME} !maintenance.html
RewriteRule ^.*$ /system/maintenance.html [L]
RewriteRule ^/$ /index.html [QSA]
Rewrite to check for Rails cached page
RewriteRule ^([^.]+)$ $1.html [QSA]
RewriteCond %{DOCUMENT_ROOT}/%{REQUEST_FILENAME} !-f
RewriteRule ^/(.*)$ balancer://mongrel_cluster%{REQUEST_URI} [P,QSA,L]

Then i finally installed the package apt-get install libapache2-mod-proxy-html libxml2-dev.Now while restarting my apache server i didn't get any error message.