title: error when exporting. apk
body: <p>killed 3 hours for this error. Search the forums did not give (anything you want)
  compiles on the emulator well. but for export if the problem</p>
  
  <pre><code>com.android.ide.eclipse.adt.internal.build.DexException: Conversion to Dalvik format failed with error 1
      at com.android.ide.eclipse.adt.internal.build.BuildHelper.executeDx(BuildHelper.java:663)
      at com.android.ide.eclipse.adt.internal.project.ExportHelper.exportReleaseApk(ExportHelper.java:204)
      at com.android.ide.eclipse.adt.internal.project.ExportHelper$2.run(ExportHelper.java:301)
      at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)
  </code></pre>
  
  <p>help those who faced</p>