I am having the same problem with all series, downloading episodes after 7 days.
I tried downloading by pid or url and neither worked. No episode detected.
I can watch episodes through flash plugin and browser only.
The search index has also changed.
What commands do I need to use now?

Before anybody responds without investigating, it appears that now whole series are online for a month after transmission and I can watch them in a browser but not stream them with get_iplayer.

Hi piddigger,
We know programmes are now available for 30 days and changes have been made to make use of this. We also know that the feeds get_iplayer used for the cache have now been removed /topic...available/

First thing for you to do is update to the latest version of get_iplayer which contains fixes for things that the change to 30 day availability broke.

At the moment you can ONLY download programmes by PID (one at a time) as there is no search index to download from.

user-2 plans to release an interim update tomorrow which will hopefully restore some of the search index and will allow you to download multiple PIDs in one go.