Magento / Server Expert Required (quick job)

Hello, I am looking for a trusted person to fix a few admin related issues & a bit of file management. Admin Issues: 1.) My website runs on Magento. I haven't used the website much lately after transferring from one server to another. I think there may have been a few things transferred incorrectly as I receive warning emails from my server host. You must solve the below.... " IMPORTANT: Do not ignore this email. Your hostname ("hidden") could not be resolved to an IP address. This means that /etc/hosts is not set up correctly, and/or there is no dns entry for "hidden". Please be sure that the contents of /etc/hosts are configured correctly, and also that there is a correct 'A' entry for the domain in the zone file. Some or all of these problems can be caused by /etc/[login to view URL] being setup incorrectly. Please check that file if you believe everything else is correct. You may be able to automatically correct this problem by using the 'Add an A entry for your hostname' option under 'Dns Functions' in your Web Host Manager. " 2.) Magento admin user login. I've been having trouble logging into Magento admin backend. I receive a page error: Nginx 500 internal server error. People have solved it in forums, but I don't understand. You may be required to reset usernames & passwords, document these changes. # Login Type # URL # Username # Password These details must then be stored in an encrypted & password protected electronic brief case which I can take with me where ever I go. These details must not be shared or distributed of course. ...................................................................... The person I will award will have outstanding reputation as I require someone who is trusted. Look forward to chatting. Thanks, Jason