The application is still being used and its website as well as the download are working just fine. If you can't search for any file, it means there is something preventing the software connecting to the search server, most likely a Firewall. Access Start > Control Panel > System and Security > Windows Firewall. Use the menus on the left to allow the application to communicate with Internet (search servers). Additionally, you might have encountered a maintenance session which in this case you need to try later.
