Install Failed - Could Not Detect Internet

My attempt to install Bitdefender Antivirus Free Edition failed when it produced a message saying it needed an internet connection.

My internet access was fine at the time - other web applications were connecting ok.

Is this a known issue?

(The failure happens after other security software has been uninstalled. I don't want to try again unless I know it'll work, as I'd keep needing to uninstall protection I put in place, and this would get tedious if Bitdefender keeps encountering the same problem.)

Thanks.