One that that often helps is to go to the DreamHost panel for Manage Domains, then click Edit for your Fully Hosted domain. Don't make any changes, but click Save. This often refreshes the configuration and clears up some issues.
When I look up your domain, I get one IP address for prifaynigeria.com, but one additional IP address for www.prifaynigeria.com. I've not seen this before, though it points to the same server. Check DNS for your domain (also under Manage Domains) and see if there are any stray entries for www. Since prifaynigeria.com redirects to the www, this may be the cause.