Here's the line:

..Pivotfields(ls_measures(ln_measure, 0)).Orientation = xlHidden

With block is set to ActiveChart.PivotLayout.PivotTable.

ls_measures is a string array (0 to 5, 0 to 3). (x, 0) contains the
caption; (x, 1) contains the data field function; (x, 2) contains the
pivottable field name; (x, 3) contains the number format.

It fails on ls_measures(5, 0), a caclulated field (run time error '1004';
unable to set the orientation property of the pivotfield class). I'm current
on SPs and updates.