A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
This is the only workaround you need to select the heading click on sort under pivot table options, click more options, then click off Autosort, and try to save the file.
However there is VBA code for excel 2000 to turn off autosort: http://support.microsoft.com/kb/235537
check if you can find 1 for excel 2007