title: How to fix the error Unable to execute dex: Multiple dex files define Lcom/google/android/gcm/GCMBaseIntentService;?
body: <p>I constantly get following two errors:</p>
  
  <pre><code>[2012-12-09 21:39:50 - Dex Loader] Unable to execute dex: Multiple dex files define Lcom/google/android/gcm/GCMBaseIntentService;
  [2012-12-09 21:39:50 - TimeTable] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lcom/google/android/gcm/GCMBaseIntentService;
  </code></pre>
  
  <p>I am new to Android so I didn't succeed it on my own.</p>