Free shipping module error

[dcase]

After completing the entire Zen Cart site (http://www.startingequipment.com), my client has decided that he wants to give free shipping on items that are above $1700 his cost (have to love these last minute additions ). However, when I go to add free shipping to an item, it notifies me to install the free shipping module. Simple enough.. or so I thought. When I go to install this module from the shipping menu, I get the following error: WARNING: YOU HAVE DUPLICATE SORT ORDERS WHICH WILL RESULT IN CALCULATION ERRORS
PLEASE CORRECT THESE ISSUES NOW!

Does anyone know what this could have caused this? To be quite honest.. I'm not even sure what it's referring to

[Kim]

When you set up a module, you add a number that determines what order they display in, that is the sort order and you have 2 "sort order" numbers that are the same. Change one of them.