I have written an addin using VB.Net and the inserting of a dxf file works sometimes while doesn't other times.

Here is the code I am using based on examples found online.Any suggestions why it isn't working?

      'Clean DXf for Laser Filter.

        CleanDXF(sDwgFileName)

        Dim dxfExtents() As Double

        dxfExtents = getExtentsofDXF(sDwgFileName)

        Dim Xscale As Double

        Dim Yscale As Double

        Xscale = dxfExtents(0) / 9

        Yscale = dxfExtents(1) / 6

        swModelDocExt.InsertObjectFromFile(sDwgFileName, False, 4, 10.0 * 0.0254#, 2.3 * 0.0254#, 0)

        importData = swApp.GetImportFileData(sDwgFileName)

        'Unit

        importData.LengthUnit("") = swLengthUnit_e.swINCHES

        'Paper size

        bRet = importData.SetPaperSize("", swDwgPaperSizes_e.swDwgPapersUserDefined, 8.5#, 11.0#)

        'Position

        bRet = importData.SetPosition("", swDwgImportEntitiesPositioning_e.swDwgEntitiesSpecifyPosition, 0, 0)

        'Import method

        importData.ImportMethod("") = swImportDxfDwg_ImportMethod_e.swImportDxfDwg_ImportToExistingDrawing

        If Xscale > Yscale Then

            bRet = importData.SetSheetScale("", 1.0, Xscale)

        Else

            bRet = importData.SetSheetScale("", 1.0, Yscale)

        End If

        'Import file with importData

        swFeat = swFeatMgr.InsertDwgOrDxfFile2(sDwgFileName, importData)

        If swFeat Is Nothing Then

            MsgBox(sDwgFileName + " geometetry was not imported into a new view.")

            Exit Sub

        End If