To get a Python module like PIL to work with the Python installed with Softimage, you will need to edit the registry. I tested this on my system, where I do not have any Python installed, except the Python installed with Softimage.
The PIL installer is looking in the registry for that Python install path, so we must edit the registry to put in the path to the Softimage Python.
You can use regedit to add the registry entry
Then set the “(Default)” value to
C:\Program Files\Autodesk\Softimage 2011 Subscription Advantage Pack\Application\python
If you do have an external Python installed, you can just temporarily change the “(Default)” value to point to the Softimage install of Python.
Hat Tip: leendert68
Also: mabxsi suggests an alternative approach that avoids editing the registry