Comment #5 on issue 1455 by [email protected]: Windows & MusicXml2Ly - problem with spaces in paths and filenames
http://code.google.com/p/lilypond/issues/detail?id=1455
By the way, if Python is in another directory (say "C:\Program Files (x86)\LilyPond\usr\bin\python.exe") then the proposed change won't work as Windows will ask what to do for opening a .py file.
