When I try to log in, I get redirected to another page with username and password fields, but every time I submit, it just blanks the boxes
Cookies are disabled on your browser. These are required for the site to operate.
Internet Explorer Open Settings -> Internet Options -> Privacy Click Sites, then type fly-euroharmony.com and click 'Allow'. This should resolve your problem
Firefox Open Settings ->Privacy Firefox will: if set to 'use custom settings', the Accept cookies from sites option must be ticked, all other settings will work (eg 'Remember History').