In our computers we are using

Python 2.7.6 and Munkres 1.0.8
Python 2.7.12 and Munkres 1.0.12

Looking at the Munkres documentation (http://software.clapper.org/munkres/#get...) I see the following:

"As of version 1.1.0, munkres no longer supports Python 2. If you need to use it with Python 2, install an earlier version (e.g., 1.0.12): pip install munkres==1.0.12"

What version of munkres do you have (pip show munkres)? You could try to install 1.0.12 to see if it works.