Is it possible to pass a parameter to a python script?

I assume you are doing this as part of your query (instead of through a Python visual, in which your parameter wouldn't get passed).  Does it work with you hard code in a file name?  If that is working, I would edit the M code in the Advanced Editor instead of in the pop-up window.  There you should be able to replace the hard-coded filename with "&File&"  (I assume the whole Python code is surrounded in double quotes in Advanced Editor and this will break it apart and insert in your paramter value.

Regards,

Pat