Well firstly, why is your username your email address(not very safe)....
Ok, FTP is simple. More than likely you can't just type that in your browser, unless you have IE6.
I would recommend you download a small FTP program, like
Filezilla. It is small and free and a nice secure way of using FTP.
Once you have an FTP program, just open it up. You can then type in 'ftp.mydowmain.x10hosting.com' in the address. There will be a username and password field as well. Just put your FTP username and password for your x10 site there(should be the same as cPanel login I believe).
Then you can log in and you will see your computer files as well as the files on you server. Just find the file on your computer and copy it over