For whatever reason, your computer decides that certain files are "special", and that only administrators can change them. If your account is an administrator, then, as I recall, you need to move the export_descr_unit file out onto the desktop, change it, save it, then move it back into the data folder. That should circumvent the problem. Otherwise, you may have to change the properties of the file to make it not 'read-only'.
"Freedom is never more than one generation away from extinction." - Ronald Reagan
"Judge them not by the color of their skin, but by the content of their character." - Martin Luther King, Jr.
"Pick up a rifle and you change instantly from a subject to a citizen." - Jeff Cooper
"I like my enemies like James Bond likes his martinis- shaken, not stirred."
My first book, The King's Own