Hi,
I guess that the variable wksData in your code is for Sheet1. And then you try to add a new column to Sheet2 by using this line wksData.AddCol();. Of course it will not add the new created column to Sheet2, because the AddCol() method is called by variable wksData, which is for Sheet1.
To add a new column to Sheet2, you should use the variable which is for Sheet2. Please try the following code.
WorksheetPage wpData = wksData.GetPage(); // get Sheet1's page
wpData.AddLayer("Sheet2"); // add one more sheet to page, named Sheet2
Worksheet wksData2 = wpData.Layers("Sheet2"); // get Sheet2
wksData2.AddCol(); // add a new column to Sheet2
Penn