Which Os you are using?
I am using windows 8 in laptop.
Please uninstall eSim and its dependencies. If you are using windows OS, go to control panel, remove eSim and its dependencies(kicad, ngspice,pyqt4,matplotlob). Deactivate the antivirus.Download eSim from the website. you can download from link:http://esim.fossee.in/downloads.
Run the setup file as administrator and also open the eSim icon as administrator.
If you are getting error again. Go to console window. Set the path where the eSim has installed.The default location is C:\\eSimChange directory to this location. cd C:\\eSim\\src\\frontEnd\\ Then type : python Application.py
Let me know the error.