> I couldn't download the ubuntu package, as download.fpcomplete.com is unreachable here.

download.fpcomplete.com is served directly from an S3 bucket. You can try replacing download.fpcomplete.com with s3.amazonaws.com/download.fpcomplete.com (e.g. http://s3.amazonaws.com/download.fpcomplete.com/ubuntu/fpco....), and see if that helps. Either way, I'd be interested to know who your ISP and/or if you're behind a corporate or national firewall.