当文件夹为空的时候，打不开文件夹

[hit_pp]

if(e.getClickCount()==2){
InstallData data = (InstallData)list_remote.getSelectedValue();
if(!data.getText().contains(".")){
if(ftp.serverIsOpen()){
try {
ftp.cd(remotePath+data.getText()+"/");
remotePath = remotePath+data.getText()+"/";
refreshRemotePath();
loadRemoteFile();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}else{
JOptionPane.showMessageDialog(MainFrame.this, "The server has been shut down, the operation fails","error",JOptionPane.ERROR_MESSAGE);
}


以上是程序的关键代码，当点击空文件夹的时候，打不开。第一次点击空文件夹没有反应，第二次点击的时候出现以下错误，请各位大侠解决一下：java.io.FileNotFoundException: CWD /wang/wang/: 550 CWD command failed. "/wang/wang/": directory not found.