AsyncFileUpload and Label which is Runat Server

on AsyncFileUpload_UploadedComplete event of ASyncFileUpload,I am doin the followin:

string filepath=MapPath("~/Uploads/") + AsyncFileUpload1.FileName;
if (AsyncFileUpload1.HasFile)
{
if (!File.Exists(filepath))
{
//file upload logic
}
else
{

lblMsg.Text = "File with the same name already uploaded.";

}
}

When i Run the code in browser->the lblMsg.Text IS GETTING SET TO "File with the same name already uploaded."...BUT ITS NOT SHOWING IN THE BROWSER..PLEASE HELP

Thanks and Regards,
Hoosha Boosha