You'll want to use ProcessBuilder to get the results. Example - Procedure for installing python libraries from source - #16 by PGriffith
My guess though is it has to do with how you are formatting your file paths. I would try Did not have my coffee yet. I think the forward slashes should be ok. Use process builder and see what you get.system.util.execute([r'C:/Python/python.exe', r'C:/LoadFlex/GetForecast.py']) The / is an escape character so you either need to do \\ to make a single / or you can put the 'r' in front to indicate it is a "raw" string and then \ no longer functions as an escape character.