On looking at the error, it looks like the document active window is in the NormalView or ReadingView. You would have to set the View to wdPrintView (or one of the other choices) before proceeding to the oWord.ActiveWindow.ActivePane.View.SeekView command.
oWord.ActiveWindow.ActivePanel.View = wdPrintView
oWord.ActiveWindow.ActivePane.View.SeekView = WdSeekView.wdSeekCurrentPageHeader;
logoCustom = oWord.Selection.HeaderFooter.Shapes.AddPicture(logoPath,
logoCustom.Select(
logoCustom.Name =
logoCustom.Left = (String logoPath = GetImgPath();ref oFalse, ref oTrue, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing);ref oMissing);"CustomLogo";float)WdShapePosition.wdShapeLeft;
oWord.ActiveWindow.ActivePane.View.SeekView = WdSeekView.wdSeekMainDocument
Arasu Elango