Nameservers work (assuming you are talking about qureshi-impex ).
The error messages are because your server has not set up the map between your domain name and your account. That takes up to 24 hours and happens to a lot of people. It is due to the fact that so many people add domians on a server that they have to be done in batches.
Please be patient and clear your browser cache and history before checking your site again.
If the default web site page has not gone in 36 hrs, post back here.