Can a mother ask for more child support

I am the father and have now gained full sole custody of my 17 year old son by court order. I have satisfied my total child support order to the courts of massachusetts as of December 2010.

The mother is now claiming that she thinks I owned a business many years ago (which i did not) and that I owe her money not stipulated by the courts. Can she file for more child support order now that I gained custody of my son?