BBC iPlayer downloads

[#1]

I am able to watch programmes through streaming ok, but have been unable to download, despite having installed the Download Manager. When attempting to download a programme I get the message:
'Download Manager cannot connect to the server. Please ensure that your computer and router settings are correct as detailed in this guide'
I have tried making all the adjustments suggested, and have even tried turning off the firewalls temporarily. I have also tried via the Mozilla browser. All to no avail. Does anybody have any ideas please? Thanks

[#2]

Do you have the PlusNet broadband firewall on? That might block the ports.
Accessible here https://portal.plus.net/my.html?action=firewall

[#3]

You have to enable popups but that may be irrelevant here.

[#4]

The Beeb allow anyone with a browser which imitates an iphone to download DRM-free files.
They have recently applied a fixed (publicly known) key to portions of these files.
Alternatively, if you have Ruby installed, you can do the downloads - Google for "iplayer-dl"
and
if you have Perl installed you might want to visit http://beebhack.wikia.com/wiki/Beebhack
Of course you should delete your download within 7 days of the broadcast.