Linux Power Management – Hook for Running Scripts on Wake

If you have gnome-control-center installed, run gnome-mouse-properties and visit Touchpad tab and click on Two-finger scrolling:

It works very well, and across wake-ups too. So, unless you are using your scripts for something else too, throw them away :)

You could try the pm-utils package.
I don't know if this is installed by default on Ubuntu.
You can then write a hook script (at e.g. /etc/pm/sleep.d/00_my_resume_hook) such as

#!/bin/sh
case "${1}" in
    hibernate)
        # nothing
    ;;
    resume|thaw)
        #your script here
    ;;
esac

I may have glossed over some essential details here.