Cant download warmane

I was thinking about playing my old characters that i had on warmane wrath of the lich king server but when i tried to download i got a message that said firefox doesnt know how to open this address and i might need to install other software to open it. Anyone know how to fix this because i heard that bittorrent is possibly illegal or something like that so im not sure.

You need bittorrent to download and yes, in most countries downloading **** is illegal but depending on your country chances of them catching you go from certain to very slim.