I have used LINEST to provide polynomial coefficients in Excel97 through
Excel 2002 with no problems. My company has loaded Excel 2003 and now all the
existing spreadsheets give the wrong answers but no error messages. I have
read the KB articles on LINEST in 2003 and none give a clue to the problem.

I use two columns of data for x and y with in this example a row of 7 cells
highlighted with this array formula:

=LINEST(AN3:AN11,AM3:AM11^{1,2,3,4,5,6})

Excel 97 -2002 dutifully reports 7 cells with the coeffs of
X6,X5,X4,X3,X2,X1 & X0
Excel 2003 sets X^6 to zero regardless of the data set and reports a wildly
wrong value for the constant.

I have tested this on a clean build of Excel 2003 with the Analysis Tool
pack loaded as well as several of our 8000 corporate desktops. I cannot find
any reference to this insidious problem on the internet, has anyone else
experienced it?