Connecting to a site(editing host file)

I am having difficulties connecting to a site, but i can't. There is an option to edit the host files, but when i add the line i need, i want to save the host file, it says i can't save it, i don't have permission and i need to contact the admin. How can i solve this, how can i save the changes i made?

I was told this is a helpful forum, will i get any help?