Hello Ravi,
Let me ask you few questions first. Did you registered for vzaar account? Did you created vzaar API token for your application?
There is no need to install anything, you just copy files we provided on Google Code to your web site, put there your API token and API secret (which is your vzaar username) and basically that's it.
Regards,
Evi Skitsanos
vzaar API Head of Support
email: e...@vzaar.com | skype: skitsanos | cell: (941) 840-0716 | twitter: http://twitter.com/skitsanos
Development hub: http://developer.vzaar.com/ | API libraries: http://code.google.com/p/vzaar/