If trying to change TranslateIt! services keyboard shortcuts you receive the following message:
You don't have permissions to change the keyboard shortcuts.
this means that you don't have permissions to write to files inside the TranslateIt! application bundle. And since the keyboard shortcuts settings are stored within that bundle, you are unable to change them.
Note: If you don't have administrator privileges, you will not be able to change the permissions of the TranslateIt!.app bundle.