I don't know how useful this is for you but I'm going to send it anyway. I can confim that the gstreamer-0.10 bug was present on my system using the Debian kernel 2.6.18-3. The libvisual package you supplied corrected the problem.
iBook G3 12.1" 700 MHz
640 MB RAM
I'm pretty sure the model is this one:
under the heading: 'M8602LL/A'
If you need any more info on the system specs or any other additional info at all then let me know and I will be happy to provide it. As I've already said I'm really new to Linux on PPC and I'm still finding my feet.