A zone record already exists for indianrealestatenews.in. However, it looks like your domain is not pointing to WordPress.com name servers yet:
http://en.support.wordpress.com/domain-helper/?host=indianrealestatenews.in
Please go to your domain registrar's site and log into the control panel. You will need to update the name servers as below:
NS1.WORDPRESS.COM
NS2.WORDPRESS.COM
NS3.WORDPRESS.COM
For more information, please visit the help documentation provided by the registrar and our support page:
http://en.support.wordpress.com/domain-mapping/map-existing-domain/
Let me know if you have any questions.