[UrbanSim-Users] Converting Data from Version 4.0 to 4.1.2

I have a dataset that was used previously with UrbanSim 4.0 that I would
like to use with version 4.1.2.

I thought I would just be able to create a new cache with which to run
UrbanSim by using create_baseyear_cache.py in version 4.1.2. I can create
the cache without any trouble, but when I try to run UrbanSim with my newly
created cache I get the following error (more detail in attached file). Is
there some reason why this shouldn't work? If so, how would I be able to get
it to work?

Any suggestions welcome,
Zak

Traceback (most recent call last):
  File "run_simulation_on_baseyear_cache.py", line 95, in ?
    ForkProcess().fork_new_process('opus_core.tools.start_run',
resources=config
)
  File "c:\opusworkspace\opus_core\fork_process.py", line 53, in
fork_new_proces
s
    raise StandardError("Problem with %s" % module_name)
StandardError: Problem with opus_core.tools.start_run

***************************************************************
* Zachary Patterson *
* Transport and Mobility Laboratory *
* School of Architecture, Civil and Environmental Engineering *
* EPFL - Ecole Polytechnique Fédérale de Lausanne *
* GC A3 398 *
* Station 18 *
* CH-1015 Lausanne *
* Switzerland *
* http://transp-or2.epfl.ch/pagesPerso/patterson.php *
* http://urban-utilities.epfl.ch/ *
* Phone: +41 (0)21 693 93 29 *
* Fax: +41 (0)21 693 80 60 *
***************************************************************