Inherit script - trying to modify

Hi,

I have a navigation I am trying to add a part.

Here is the script

on (release) {

          x = 0;

          y = 13;

          while (x<13) {

                    x = x+1;

                    if (y == x) {

                              //do nothing;

                    } else {

                              _root["mm" add x].gotoAndStop(1);

                    }

          }

          if (mm13DOWN) {

                    _root.mm13.gotoAndStop(1);

          } else {

                    _root.mm13.gotoAndStop(2);

          }

}

on (rollOver) {

          if (mm13DOWN) {

                    //do nothing

          } else {

                    sOV13.gotoAndStop(2);

          }

}

Can someone help me figure out how to modify it. I have duplicate the 13 symbols to 14 and moved them. When I change the mm13 to 14 it does not work?

Thanks!