버튼을 누르면 커스텀다이얼로그가 떠야되는 프로그램인데.. 안뜨고.. 에러나요.. 왜그럴까요??? ㅠ.ㅜ

일단 xml 생성했구요..
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:id="@+id/layout_root"
 android:orientation="horizontal"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:padding="10dp">
  <ImageView
   android:id="@+id/image"
   android:layout_width="wrap_content"
   android:layout_height="fill_parent"
   android:layout_marginRight="10dp"
   />
  <ImageButton
   android:id="@+id/text"
   android:layout_width="wrap_content"
   android:layout_height="fill_parent"
   android:textColor="#FFF"
 />
</LinearLayout>


java파일에..
  Context mContext = getApplicationContext();   
  Dialog dialog = new Dialog(mContext);   
  dialog.setContentView(R.layout.custom_dialog);   
  dialog.setTitle("커스텀 다이얼로그");   
  TextView text = (TextView) dialog.findViewById(R.id.text);   
  text.setText("Hello, this is a custom dialog!");   
  ImageView image = (ImageView) dialog.findViewById(R.id.image);   
  image.setImageResource(R.drawable.icon);

이렇게 썼거든요???
근데 왜 안될까요??? ㅠ.ㅜ
알려주세여~~ -0-