proxy: No protocol handler was valid for the URL

While trying to configure mod_proxy_balancer.Although i configured everything correctly and enabled all required modules(mod_proxy, mod_proxy_http).But after restarting the apache server i used to get internal server in my browser.Then i verified the apache error log

[warn] proxy: No protocol handler was valid for the URL /login.html. If you are using a DSO version of mod_proxy, make sure the proxy submodules are included in the configuration using LoadModule

After searching a lot in google i got tips from Serendipitous
In my terminal i created some soft links for proxy_http.load like this

ln -s /etc/apache2/mods-available/proxy_http.load \
/etc/apache2/mods-enabled/proxy_http.load

Now i restarted my server and it was working fine.For the same problem i have referred another usefull blog Kai`s Blog in that they have tried by adding a trailing slash to the url of the balancer like this

<Proxy balancer://mycluster/>
BalancerMember http://foobar.de:8080/ 
</Proxy>
ProxyPass / balancer://mycluster/ 
ProxyPassReverse / balancer://mycluster/