actionscript 3 - Adobe Air multi-download -

i have been searching both web , stackoverflow complete answer implementing multiple downloads of mp3 files downloadmanager. have read number of post , realize efficient facilities use bytearray, urlstream , filestream saving t disk. have implemented follows:

<?xml version="1.0" encoding="utf-8"?> <s:windowedapplication xmlns:fx="http://ns.adobe.com/mxml/2009"  xmlns:s="library://ns.adobe.com/flex/spark"  xmlns:mx="library://ns.adobe.com/flex/mx"      creationcomplete="downloadfiles()"> <fx:declarations>  </fx:declarations> <fx:script> <![cdata[ import flash.filesystem.*; import flash.net.urlstream; public var stream:urlstream; public var filedata:bytearray; public var filestream:filestream; public var file:file;  public var trackstring:string; public var filearray:array; public var urlreq:urlrequest;  private function downloadfiles():void { filearray = new array(); filearray[0]="crazy"; filearray[1]="distant lover"; filearray[2]="easy going"; filearray[3]="give in love"; filearray[4]="muzicageerotic moods"; filearray[5]="muzicagegive in love"; filearray[6]="muzicagepieces of dreams"; filearray[7]="muzicagethere never you"; filearray[8]="remembered"; filearray[9]="teach me tonight";   downloadnextfile(); } private function downloadnextfile():void{ trackstring = filearray.shift(); urlreq = new urlrequest("http://localhost:8080/multidownloadsampleapp7- debug/muzicage/"+trackstring+".mp3"); stream = new urlstream(); file = file.documentsdirectory.resolvepath("c:/users/development/test/"+trackstring+".mp3");  filestream = new filestream();  stream.addeventlistener(progressevent.progress, progressbar);  stream.addeventlistener(event.complete, writecomplete);  stream.load(urlreq);   }  private function writecomplete(evt:event):void {      filedata = new bytearray();      stream.readbytes(filedata,0,stream.bytesavailable);  filestream.openasync(file, filemode.write)      filestream.writebytes(filedata,0,filedata.length);      filestream.close();          stream.removeeventlistener(progressevent.progress, progressbar);      stream.removeeventlistener(event.complete, writecomplete);   downloadnextfile(); }   private function progressbar(evt:progressevent):void {      // progressbar   }  ]]> </fx:script> </s:windowedapplication> 

although appears capture , save mp3’s disk receiving following error message.
error #2044: unhandled ioerrorevent:. text=error #2032: stream error. @ multidownloadsampleapp7/downloadnextfile()[c:\users\development\newgageprojects\multidownloadsampleapp7\src\multidownloadsampleapp7.mxml:40] @ multidownloadsampleapp7/writecomplete()[c:\users\ development \newgageprojects\multidownloadsampleapp7\src\multidownloadsampleapp7.mxml:59] [unload swf] multidownloadsampleapp7.swf

when close error , in save directory find mp3’s requested in array.

it doesn't you're checking see if you've finished downloading files before call downloadnextfile().

so error gets end of array , tries generate urlrequest null string.