Android emulator has stopped unexpectedly.How to Rectify it?

I am new to Android Development.

I am using Eclipse.

I copied the snake game from the sample example.

When I try to run it the following things are displayed on the console:

11-06-01 20:11:32 - Snake] Android Launch!

[2011-06-01 20:11:32 - Snake] adb is running normally.

[2011-06-01 20:11:32 - Snake] Performing
com.example.android.snake.Snake activity launch

[2011-06-01 20:11:32 - Snake] Automatic Target Mode: Preferred AVD
'Pratyush_android' is not available. Launching new emulator.

[2011-06-01 20:11:32 - Snake] Launching a new emulator with Virtual
Device 'Pratyush_android'

[2011-06-01 20:11:33 - Snake] New emulator found: emulator-5554

[2011-06-01 20:11:33 - Snake] Waiting for HOME
('android.process.acore') to be launched...

[2011-06-01 20:11:54 - Snake] WARNING: Application does not specify an
API level requirement!

[2011-06-01 20:11:54 - Snake] Device API version is 4 (Android 1.6)

[2011-06-01 20开发者_运维百科:11:54 - Snake] HOME is up on device 'emulator-5554'

[2011-06-01 20:11:54 - Snake] Uploading Snake.apk onto device
'emulator-5554'

[2011-06-01 20:11:54 - Snake] Installing Snake.apk...

[2011-06-01 20:12:06 - Snake] Success!

[2011-06-01 20:12:06 - Snake] Starting activity
com.example.android.snake.Snake on device emulator-5554

[2011-06-01 20:12:11 - Snake] ActivityManager: Starting: Intent
{ act=android.intent.action.MAIN
cat=[android.intent.category.LAUNCHER]
cmp=com.example.android.snake/.Snake }

On the screen of the Emulator, it says:

SCREEN is LOCKED ,Unlock it by pressing Menu

When I Press Menu, there is a message box:

The application(process com.example.android.snake) has stopped
unexpectedly.
Please try again.

What could be causing this?