I don't think that's possible.
Thanks Peter, is there another way to avoid any users intervention while running script/other .net tools? I believe we can hide the screen while running the script, in the same way, is ther any other option to meet this requirement?
While the script is running, if it is properly written, the user should not be able to interfere with the workings of the script. as a extra measure, try using a scriptUI palette with a progress bar (see peter's book on the subject).
Are you using stuff like "app.copy()" and app.paste()? That it is usually a recipe for disaster, and the one reason people ask about locking the keyboard.