File upload not working using URLRequest in flex
<form id="avatar" enctype="multipart/form-data"
           action="http://localhost:8080/alfresco/service/slingshot/profile/uploadavatar?
                  alf_ticket=TICKET_7475e180e8d258c0341fc745a3a35274d0a06e50"
           method="post">

     <input type="text" name="username" value="ken"/>

<input type="file" name="filedata" />
    <input type="submit" name="button" value="upload" / /form

var uploadURL:URLRequest = new URLRequest();
uploadURL.url="http://localhost:8080/alfresco/service/slingshot/profile/uploadavatar?alf_ticket=TICKET_7475e180e8d258c0341fc745a3a35274d0a06e50"";
uploadURL.method=URLRequestMethod.POST;
uploadURL.contentType="multipart/form-data";
var params:URLVariables = new URLVariables();
params.username ="admin";
params.filedata=fileRef.data;
uploadURL.data = params;
fileRef.upload(uploadURL)