the error code shown when download window is opened

sbIAsyncForLoop::eval( this.m_FinishedEval )

function webPlaylist_finishedEval() {
if (!this.m_Interval) {
return;
}
var mediaList = aMediaListView.mediaList;
var library = mediaList.library;
var foundItemsLength = this.items.length;
if (foundItemsLength) {
if (context) {
context.playlistHasItems = true;
context.showPlaylist = true;
}
var self = this;
var mediaItemsToScan;
var batchFunction = function () {if (mediaList.length) {mediaList.clear();}for (var index = 0; index < foundItemsLength; index++) {var item = self.items[index];var mediaItem = null;if (item instanceof Components.interfaces.sbIMediaItem) {mediaItem = item;} else {var url = item;var name = "";if (item instanceof Object) {url = item.url;name = item.name;}try {var mainLibrary = LibraryUtils.mainLibrary;var listener = {foundItem: null, onEnumerationBegin: function () {return Components.interfaces.sbIMediaListEnumerationListener.CONTINUE;}, onEnumeratedItem: function (list, item) {this.foundItem = item;return Components.interfaces.sbIMediaListEnumerationListener.CANCEL;}, onEnumerationEnd: function () {}};LibraryUtils.mainLibrary.enumerateItemsByProperty(SBProperties.originURL, url, listener);if (listener.foundItem) {mediaItem = listener.foundItem;}} catch (err) {}if (mediaItem == null) {var propArray = [[SBProperties.originPage, self.currentURL], [SBProperties.originPageImage, self.currentURL], [SBProperties.originURL, url], [SBProperties.originPageTitle, self.currentTitle], [SBProperties.enableAutoDownload, "1"], [SBProperties.downloadButton, "1|0|0"]];if (name.length > 0) {propArray.push([SBProperties.trackName, name]);}var uri = newURI(url);mediaItem = library.createMediaItem(uri, SBProperties.createArray(propArray));if (!mediaItemsToScan) {mediaItemsToScan = Components.classes[CONTRACTID_ARRAY].createInstance(nsIMutableArray);}mediaItemsToScan.appendElement(mediaItem, false);}}mediaList.add(mediaItem);}};
mediaList.runInBatchMode(batchFunction);
if (mediaItemsToScan && mediaItemsToScan.length) {
var metadataService = Components.classes['@songbirdnest.com/Songbird/FileMetadataService;1'].getService(Components.interfaces.sbIFileMetadataService);
metadataService.read(mediaItemsToScan);
}
} else if (this.child == false) {
if (!this.checkForAnything(this)) {
library.remove(mediaList);
false;
delete aMediaListView;
}
}
if (this.child == false) {
context.progressTotal = context.progressCurrent = 1;
}
}

[Exception... "Component returned failure code: 0x8000ffff (NS_ERROR_UNEXPECTED) [sbIMediaList.runInBatchMode]" nsresult: "0x8000ffff (NS_ERROR_UNEXPECTED)" location: "JS frame :: chrome://songbird/content/scripts/asyncWebPlaylist.js :: webPlaylist_finishedEval :: line 323" data: no]