Ubuntu :: Error While Installing Software Written In Python

For example, I want to install a texteditor called Editra, i done it like the following

First, I install the Editra
sudo apt-get install Editra - success ,its version is 0.5.30

Second, I run it in Terminal
Editra - it can work,but with the error infos "(python:1682): Gtk-CRITICAL **: gtk_widget_add_accelerator: assertion `GTK_IS_WIDGET (widget)' failed"

Third, I used command line "dpkg -L Editra", and found that the Editra is installed under /usr/share/pyshared/Editra,so i created the .desktop like this
sudo gedit /usr/share/applications/Editra.desktop

[Desktop Entry]
Encoding=UTF-8
Name=Editra
Comment=the Best TextEditor
Exec=/usr/share/pyshared/Editra
Icon=/usr/share/pyshared/Editra/pixmaps/editra.png
Terminal=false
Type=Application
Catergories=Development

It showed, and I clicked it for running, but it told me error infos
Could not launch 'Editra'
Failed to execute child process "/usr/share/pyshared/Editra" (Permission denied)
Not just Editra, so many software that written in python have the same question, such as tortoisehg...