[dublin]

All these links are of mp4, nothing indicates .f4m.
Where can I find the correct link ?

Well it seems that iPlayer Ondemand videos are not using adaptive streaming. So you must use rtmpdump to donwload those files.
But no worries here's how-to example:
http://pastebin.com/8Tfpwgsx
If that seems too complicated use RTMPExploreX to download.
https://github.com/andr3jx/RTMPExploreX

Edit:

Do I have anything wrong with the installation ?

C:\Documents and Settings\Administrator>php AdobeHDS.php --manifest "http://stream.fora.tv/h12084/2011-09-22_kirshembaum_FORAcast-4x3-384kbps-12084.f4m" --delete

Could not open input file: AdobeHDS.php

I'm guessing AdobeHDS.php is not in C:\Documents and Settings\Administrator> folder....?