The simple blender model for Sintel Animation Sprint seems to have stopped working for Blender 2.56, this is likely because a RNA renaming.
The URL for the original model is http://storage.cessen.com/perm_links/2010/durian/simple_adult.blend
I updated the RNA to make it Blender 2.56 enabled, also I added a useful ManCandy functionality to Hide/Show parts of the mesh.
Please check it out and let me know if there is anything is wrong, my email is l3c_lara(at)yahoo.es
I made it for current version of Blender 2.56, I am not sure if it will work in new versions.
This is a Durian asset, so I think it should be licensed as CC-BY-SA
Have fun, LC