Fundraising Plug-in: Can't install

I just purchased the Fundraising Plug-in, but am unable to install it. I followed the instructions provided by 1) downloading the plug-in, 2) saving the files to my hard drive, 3) downloading File-Zilla.

Now here's where I got stuck. As instructed, I put in my domain name, username, and password into the FileZila. However, every time I do so, it says "Could not connect to server." What am I missing? Is there an easier way to do this?