I have released a Software which helps you to use ensymble.py...
download it from xils.net -> downloads -> series 60 -> EnsymbleGUI
download ensymblegui 0.5.0 full and unpack it in c:\ensymble
then download ensymblegui 0.6.5 light and replace the ensymblegui.exe in c:\ensymble
(you can also only download version 0.6.5 and use your existing ensymble.py files or download them, in version 0.5.0 full all needed files (except for python 2.5 win version) are included, though it is not recommended to use version 0.5.0 anymore because of many enhancements in version 0.6.5)
then start ensymblegui.exe click on the ? and move the window away from the main screen. then set the python file you want to use py clicking on it in the file window, then if you whish to, click on the svg button (under the files window) and click on the svg icon file you want to use, then leave every other edit box blank.
Now try to click on Create SIS and look into the log window wheter ensymble.py outputs any error.