Error: Unable to set the Orientation property of the PivotField class

[Devotchka]

I have Excel 2003. I have 2 different data fields being pulled into the area vol_net and vol_gross and for some reason when there is a lot of data the table freaks out and comes up with the orientation error.

With ActiveSheet.PivotTables("PivotTable3").PivotFields("vol_net")
.Orientation = xlDataField
.Caption = "Sum of vol_net"
.Position = 1
.Function = xlSum

The error is on the 2nd line in .Orientation = xlDataField

Any help would be appreciated!