pose_from_pdb gives RuntimeError: unidentifiable C++ exception?

I am following this tutorial:

http://graylab.jhu.edu/pyrosetta/downloads/documentation/Workshop2_PyRos...

When I get to the line:

pose = pose_from_pdb("1YY8.clean.pdb")

it results in an error:

RuntimeError Traceback (most recent call last)
<ipython-input-9-755d9c16f3f1> in <module>()
----> 1 pose = pose_from_pdb("1YY8.clean.pdb")

RuntimeError: unidentifiable C++ exception

What's wrong? I am using Ubuntu 14.04.1, PyRosetta 12.04LTS r24, and Rosetta 2014.35.57232_bundle.