Python Nmap No Such File Or Directory

Question

I'm trying to use nmap to scan for MAC addresses, but I can't get it to work. I installed nmap for Python2.7 from here: http://xael.org/norman/python/python-nmap/

Then I unzipped the file and ran

python setup.py install

Then I opened a session of python and tried this:

import nmap
nm = nmap.PortScanner()

But I get this error:

OSError: [Errno 2] No such file or directory

Why is this happening?