I am trying to open an excel 2003 workbook with custom sort in excel 2007. I
get an error that points to "a sort state that uses a sort condition with a
custom list. This information will be lost in earlier versions of Excel."

In the directions to correct the error I am instructed to "...change the
sort state so that it no longer contains a custom list.."

How do you change the sort state? Why can't excel 2007 open an excel 2003
workbook?