getting an edit control in python script crashes xbmc

I have a custom window with id 9542 and an edit control with id 30 and radio button with id 70

I want to read text entered in the edit control, so I do following in my script
the xbmc crashes with message:
Segmentation fault (core dumped)

when I try to pass id of radio button like this:
It does not crash.
So why is it crashing for edit control?

Thanks for help in advance.