Photoshop Script Change Blend Mode

I see some problem area

app.displayDialogs = DialogModes.NO;

var TemplateFile = File.openDialog ("Please select a template :", "*.psd");

var DesignsFolder = Folder.selectDialog("Please select Designs folder :");

preferences.typeUnits = TypeUnits.PIXELS;

preferences.rulerUnits = Units.PIXELS;

open(File(TemplateFile));

var DocRef = activeDocument;

var Rectangle = DocRef.activeLayer;

var Rectangle = DocRef.channels.getByName("PASTE HERE");

// The above looks odd the second set of Rectangle is not effected by the fist set

// The alpha channel can have any shape  its bounds will be a rectangle

var Selection = DocRef.selection.load(Rectangle);

var Bound = DocRef.selection.bounds ;

PosX =  Bound[0];

PosY =  Bound[1];

DimX =  Bound[2] - Bound[0];

DimY =  Bound[3] - Bound[1];

//var DesignsList = DesignsFolder.getFiles("*.psd"| "*.jpg"| "*.jpeg");  // Does not do the job for me

var DesignsList = DesignsFolder.getFiles(/\.(jpg|jpe|jpeg|psd)$/i);

var Win = new Window('dialog', 'BendMode :');

    Win.size = [150,150];

    Win.btnPnl = Win.add('panel', undefined, 'Build it');

    Win.btnPnl.rb1 = Win.btnPnl.add('radiobutton', undefined, 'Darken');

    Win.btnPnl.rb2 = Win.btnPnl.add('radiobutton', undefined, 'Normal');

    Win.btnPnl.rb3 = Win.btnPnl.add('radiobutton', undefined, 'Lighten');

    Win.btnPnl.rb4 = Win.btnPnl.add('radiobutton', undefined, 'Multiply');

       Win.btnPnl.rb1.onClick = function()

        {Win.close();    

         Exe(1);

        }

       Win.btnPnl.rb2.onClick = function()

        {Win.close();    

         Exe(2);

        }

       Win.btnPnl.rb3.onClick = function()

        {Win.close();    

         Exe(3);

        }

       Win.btnPnl.rb4.onClick = function()

        {Win.close();    

         Exe(4);

        }

      Win.show();

function Exe(Val){

    for(I=0; I < DesignsList.length ; I++ ){

        open(DesignsList);

        var TempDocRef = activeDocument;

        var N = TempDocRef.name

alert("This resize will distort images that have a different aspect ratio then the alpha chanel")

        TempDocRef.resizeImage(DimX,DimY, undefined, undefined);

        TempDocRef.selection.selectAll();

        if(TempDocRef.activeLayer.isBackgroundLayer == true){

            TempDocRef.selection.copy();

            }else{

                TempDocRef.selection.copy(true);

            }

        TempDocRef.close(SaveOptions.DONOTSAVECHANGES);

        PasteANDSave(N);

        };

    function PasteANDSave(N){

        DocRef.artLayers.add();                         // not needed paste will add a layer

//   there may be a problem  with paste if the clipboard image has a different  color profile

//   than the tenplate document it depends of the users Photoshop Color settings.

        var Selection = DocRef.selection.load(Rectangle);

        DocRef.paste();

// You could add the selection as a layer mask to shape the pasted layer to the alpha channel shape.

        if(Val == 1){

            DocRef.activeLayer.blendMode  = BlendMode.DARKEN;

        }else if(Val == 2){

            DocRef.activeLayer.blendMode  = BlendMode.NORMAL;

        }else if(Val == 3){

            DocRef.activeLayer.blendMode  = BlendMode.LIGHTEN;

        }else if(Val == 4){

            DocRef.activeLayer.blendMode  = BlendMode.MULTIPLY;

        }

        DocRef.resizeImage("1000px", DocRef.height /(DocRef.width/1050) + "px",undefined, undefined);

        var JpegOptions = new JPEGSaveOptions();

        JpegOptions.quality = 12;                                                  // I would use quality 10 to reduce file size

        DocRef.saveAs ( new File(DesignsFolder + "/result_" + N ), JpegOptions);   // would save files in a subfolder so addition templates could be populated

        DocRef.activeHistoryState = DocRef.historyStates[0] ;                      //reset Template

    }

}

DocRef.close(SaveOptions.DONOTSAVECHANGES);                                        // do not save over the template