Photoshop CS5 Action Manager Not Responding

Question

I've been trying to port CS4 panels to CS5. The code below compiles without an error. It runs without throwing a runtime error. However, every call to the action manager causes the code to stop. Comment out the action manager code and everything runs.
I also notice that the mx.Alert does not open an alert dialog. It causes the same issue. The code stops.
This code works flawlessly with CS4.
Any suggestions would be very welcome!
Mitch
private function makeLuminosityEdgeMask(maskWidth:int):void { 
try { 
var docRef : Document = Photoshop.app.activeDocument;  
var docRef2 : Document = docRef.duplicate( "Duplicate" ); 
var docName : String = docRef.name; 
docRef2.bitsPerChannel = BitsPerChannelType.EIGHT;
docRef2.flatten();
docRef2.changeMode(ChangeMode.GRAYSCALE);
var myArtLayer: ArtLayer = ArtLayer(docRef2.activeLayer); 
// Blur photo prior to mask generation for wide and medium width masks
switch (maskWidth) { 
case maskWidthMediumEdges: myArtLayer.applyGaussianBlur(1.0); break; 
case maskWidthWideEdges: myArtLayer.applyGaussianBlur(3.0); break; 
default: break;}
// Run the Find Edges filter
var idFndE:Number = Photoshop.app.charIDToTypeID( "FndE" );Photoshop.app.executeAction( idFndE,
null, DialogModes.NO ); 
// Invert result of Find Edges filter
myArtLayer.invert();
// Apply curves adjustment
var curvesShape:Array = new Array(new Array(20,0), 
new Array(60,120), 
new Array(90,180), 
new Array(145,225), 
new Array(255,255));myArtLayer.adjustCurves(curvesShape);
// Apply maximum filter
switch (maskWidth) { 
case maskWidthMediumEdges: myArtLayer.applyMaximum(1.0); break; 
case maskWidthWideEdges: myArtLayer.applyMaximum(2.0); break; 
default: break;}
// Apply median filter
switch (maskWidth) { 
case maskWidthMediumEdges: myArtLayer.applyMedianNoise(1.0); break; 
case maskWidthWideEdges: myArtLayer.applyMedianNoise(2.0); break; 
default: break;}
// Apply Gaussian Blur
switch (maskWidth) { 
case maskWidthExtraNarrowEdges: myArtLayer.applyGaussianBlur(0.1); break; 
case maskWidthNarrowEdges: myArtLayer.applyGaussianBlur(0.5); break; 
case maskWidthMediumEdges: myArtLayer.applyGaussianBlur(1.0); break; 
case maskWidthWideEdges: myArtLayer.applyGaussianBlur(2.0); break; 
default: break;}
// Apply AutoLevels to Mask
myArtLayer.autoLevels();
// Duplicate channel and rename
var channelName:String; 
switch (maskWidth) { 
case maskWidthExtraNarrowEdges: channelName = maskLuminosityEdgesExtraNarrow; break;  
case maskWidthNarrowEdges: channelName = maskLuminosityEdgesNarrow; break; 
case maskWidthMediumEdges: channelName = maskLuminosityEdgesMedium; break; 
case maskWidthWideEdges: channelName = maskLuminosityEdgesWide; break;}
// Duplicate channel to original document
var idDplc:int = Photoshop.app.charIDToTypeID( "Dplc" ); 
var desc2:ActionDescriptor = new ActionDescriptor(); 
var idnull:int = Photoshop.app.charIDToTypeID( "null" ); 
var ref1:ActionReference = new ActionReference(); 
var idChnl:int = Photoshop.app.charIDToTypeID( "Chnl" ); 
var idOrdn:int = Photoshop.app.charIDToTypeID( "Ordn" ); 
var idTrgt:int = Photoshop.app.charIDToTypeID( "Trgt" );ref1.putEnumerated( idChnl, idOrdn, idTrgt );
desc2.putReference( idnull, ref1 );
var idT:int = Photoshop.app.charIDToTypeID( "T " ); 
var ref2:ActionReference = new ActionReference(); 
var idDcmn:int = Photoshop.app.charIDToTypeID( "Dcmn" );ref2.putName( idDcmn, docName );
desc2.putReference( idT, ref2 );
var idNm:int = Photoshop.app.charIDToTypeID( "Nm " );desc2.putString( idNm, channelName );
Photoshop.app.executeAction( idDplc, desc2, DialogModes.NO );
// Close duplicate
docRef2.close(SaveOptions.DONOTSAVECHANGES);
// Release RAM;Photoshop.app.purge(PurgeTarget.ALLCACHES);
// Refresh appPhotoshop.app.refresh();
// Restore Channels palettedocRef.activeChannels = docRef.componentChannels;
catch(error:Error) {Alert.show(
"Error in makeLuminosityEdgeMask(): " + error.message);}

Answer 1

Here is the code causing a run-time problem: 
// Run the Find Edges filter
var idFndE:int = Photoshop.app.charIDToTypeID( "FndE" );Photoshop.app.executeAction( idFndE, undefined, DialogModes.NO );
The error is "NULL pointer was encountered"
This code was fine with PatchPanel and Photoshop CS4.
The second and third parameters are declared in the interface as optional. The second paramter is an optional ActionDescriptor.
Mitch