The iPlayer episode BD linked to works fine for me and should also work for you.
The latest version of Adobe FlashPlayer can be obtained from here:
http://www.adobe.com/shockwave/download/download.cgi?P1_Prod_Version=ShockwaveFl ash
You can check here: http://www.adobe.com/products/flash/about/ to see which version you should install for your Mac and OS. Note that version 10,1,102,64 is the last version available to PPC Mac users*. The latest version, 10.2.152.25 or later, is for Intel Macs only, as Adobe no longer support the PPC platform. Note that the latest Flash Player update only works on YouTube with Safari in 32 bit mode - until YouTube correct this.
* Unhelpfully, if you want the last version for PPC Macs, you need to go here: http://kb2.adobe.com/cps/142/tn_14266.html and scroll down to 'Archived Versions/Older Archives'. The first one on the list, Flash Player 10.1 is the one you download. More information here: http://kb2.adobe.com/cps/838/cpsid_83808.html
You should first uninstall any previous version of Flash Player, using the uninstaller from here (make sure you use the correct one!):
http://kb2.adobe.com/cps/865/cpsid_86551.html#prob1=uninst,os=m10.6,
and also that you follow the instructions closely, such as closing ALL applications first before installing. You must also carry out a permission repair after installing anything from Adobe.
