BuddyPress Plugin for WordPress

I installed a plugin in WordPress named BuddyPress.It installed successfully and also show the links like activity,members,groups etc.
But the links not working properly. When I click on link activity, found a error like “Oops! This link appears to be broken.” in Google-Chrome and “The requested URL was not found on this server.” in Mozilla Firefox.

So, Please help me to solve this.