文件上传异常，请高手帮帮忙，调用了webservice的。

错误的堆栈信息
System.Net.WebException was unhandled
  Message="The underlying connection was closed: An unexpected error occurred on a receive."Source="System.Web.Services"
  StackTrace:
       at System.Web.Services.Protocols.WebClientProtocol.GetWebResponse(WebRequest request)
       at System.Web.Services.Protocols.HttpWebClientProtocol.GetWebResponse(WebRequest request)
       at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
 
        if (userResponse == DialogResult.OK)
                    {     
                        FileStream fs = new FileStream(openFileDialog.FileName, FileMode.Open, FileAccess.Read);
                        BinaryReader r = new BinaryReader(fs);
                        byte[] postArray = r.ReadBytes((int)fs.Length);
                        
                        bool isSuccessful = documentService.UpLoadFile(openFileDialog.FileName, postArray, send, targetedUser.Name, senderID, receiveID);                        r.Close();
                        fs.Close();
                   }
传其他文件没问题，就是不能传MP3，不知道何解，请各位高手帮帮忙，出错是这句：    
bool isSuccessful = documentService.UpLoadFile(openFileDialog.FileName, postArray, send, targetedUser.Name, senderID, receiveID);