转换错误？急？

import java.io.*;
import javax.microedition.io.*;
import java.lang.*;

public class HelloWorldMIDlet
{
private StreamConnection m_Conn = null;
private DataInputStream m_In = null;
private DataOutputStream m_Out = null;
boolean getConnection()
{
boolean bReturn = true;
String sURL = "file://c:";
try
{
m_Conn = (StreamConnection)Connector.open(sURL,Connector.READ_WRITE,true);
}
catch(InterruptedIOException e)
{
bReturn = false;
}
catch(IOException e)
{
bReturn = false;
}
catch(Exception e)
{
bReturn = false;
}
return bReturn;
}
public HelloWorldMIDlet()
{
super();
}
public void sendOutput()
{
if(m_Conn != null)
{
try
{
m_Out = m_Conn.openDataOutputStream();
String sMsg = "action=subscribe&address=connet%40mydomain.com\n";
byte postMsg[] = sMsg.getBytes();
for(int i = 0;i < postMsg.length;i++)
{
m_Out.writeByte(postMsg[i]);
}
m_Out.flush();
m_Out.close();
}
catch(Exception e)
{
System.out.println("sendOutput:" + e.toString());
}
}
else
{
System.out.println("connection not established or lost!");
}
}
public int getInput()
{
int iCount = 0;
try
{
m_In = m_Conn.openDataInputStream();
StringBuffer sbInput = new StringBuffer("");
int iData;
for(iCount = 0;(iData = m_In.read()) > 0;iCount++)
{
sbInput.append((char)iData);
}
m_In.close();
System.out.println("received from connection:");
System.out.println(sbInput.toString());
}
catch(Exception e)
{
System.out.println("getInput:" + e.toString());
}
return iCount;
}  
public static void main(String args[])
{
HelloWorldMIDlet ce = new HelloWorldMIDlet();
if(ce.getConnection())
{
System.out.println("connection successfully established...");
    ce.sendOutput();
    System.out.println("send repuest..");
    int iReceived = ce.getInput();
    System.out.println("received input:" + iReceived +"bytes");
 }
 else
 {
  System.out.println("can't establish connettion!");
 }
}
}
 

错误：
Unable to create MIDlet HelloWorldMIDlet

java.lang.ClassCastException

at com.sun.midp.midlet.Selector.commandAction(+50)

at javax.microedition.lcdui.Display$DisplayAccessor.commandAction(+152)

at com.sun.kvem.midp.lcdui.EmulEventHandler$EventLoop.run(+459)

请哪位指教？