Apps Coding problem

[randheer]

Hi,
I have a problem in code. Mine code is:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@drawable/blue">

<TextView
android:id="@+id/label"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Type here:"/>

<EditText
android:id="@+id/entry"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@android:drawable/editbox_background"
android:layout_below="@id/label"/>

<Button
android:id="@+id/ok"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/entry"
android:layout_alignParentRight="true"
android:layout_marginLeft="10dip"
android:text="OK" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toLeftOf="@id/ok"
android:layout_alignTop="@id/ok"
android:text="Cancel" />
</RelativeLayout>


Here the problem is:
ERROR Error: No resource found that matches the given name (at 'background' with value '@drawable/ blue').

Tell me where is the problem.