I am converting a Word VBA macro to C# as part of a plugin I am coding.
I researched the options for converting the With/End With VB block to C#. And I went ahead and tried to convert my VBA PageSetup settings:
With ActiveDocument.PageSetup
    .Orientation = wdOrientPortrait
    .TopMargin = InchesToPoints(0.98)
    .BottomMargin = InchesToPoints(0.98)
    .LeftMargin = InchesToPoints(0.92)
    .RightMargin = InchesToPoints(0.92)
    .Gutter = InchesToPoints(0)
    .HeaderDistance = InchesToPoints(0.49)
    .FooterDistance = InchesToPoints(0.49)
    .PageWidth = InchesToPoints(8.5)
    .PageHeight = InchesToPoints(11)
    .LayoutMode = wdLayoutModeDefault
End With
So using @JohnSkeet's answer to this question, I wrote my C# code:
var oPageSetup = new Word.PageSetup
{
    Orientation = Word.WdOrientation.wdOrientPortrait,
    TopMargin = (float)(0.98 * 72),
    BottomMargin = (float)(0.98 * 72),
    LeftMargin = (float)(0.92 * 72),
    RightMargin = (float)(0.92 * 72),
    Gutter = (float)(0),
    HeaderDistance = (float)(0.49 * 72),
    FooterDistance = (float)(0.49 * 72),
    PageWidth = (float)(8.5 * 72),
    PageHeight = (float)(11 * 72),
    LayoutMode = Word.WdLayoutMode.wdLayoutModeDefault
};
However when doing so, I get the following compiler error:
Cannot create an instance of the abstract class or interface 'Microsoft.Office.Interop.Word.PageSetup'
Can somebody advice me on what do I do wrong and how to correct my code? Thanks in advance.