Run Python scripts from Windows command line, argument not passed
I had the same problem with Windows 7 / Python, and eventualy found that I had to set up correct file associations AND update two registry entries through regedit.
It is all described in this excelent article:
http://eli.thegreenplace.net/2010/12/14/problem-passing-arguments-to-python-scripts-on-windows/
To move the answer to SO (rather than the link in Jon's answer):
Modifying the following two registries so that the arguments are passed along to Python:
HKEY_CLASSES_ROOT\Applications\python.exe\shell\open\commandHKEY_CLASSES_ROOT\py_auto_file\shell\open\commandAdd %* to the existing "C:\PythonXX\python.exe" "%1", so that the key now looks like: "C:\PythonXX\python.exe" "%1" %*.
Source: http://eli.thegreenplace.net/2010/12/14/problem-passing-arguments-to-python-scripts-on-windows/