place images in illustrator

Hi all,

     how to place image in specific layer in illustrator using script?

     i have tried the following code.. but some times it did not worked..

     var curLayer = app.activeDocument.layers.getByName("temp");

     var itemToPlace = curLayer.placedItems.add();

i think the new placedItem added in activeLayer.. if the active layer is in locked/invisible then returns "target layer can't modified error"

how to fix that error or how to set target layer

Pls help.