I get the Error
Unable to start activity ComponentInfo{de.androidbuch.activiti/de.androidbuch.activiti.task.Activity}: android.view.InflateException: Binar
Had the same error type, where exactly the same error message in logcat was displayed. I needed to make changes in the Java Build Path located under Project->Properties. I had included Google Maps related libraries like android-support-v4.jar and google-play-services.jar; however I was missing including these on the 'Build class path' in the 'Order and Export' option menu. Maybe the error lies here.
Try including libraries to the build class path.
The order of which the classes are built might also trigger the error, so my advice is also to try to rearrange the order of the building path. The error disappeared when I used the following order: 'my_project_name/src'->'my_project_name/gen'->'Android Private Libraries'. The last unit contains the jar files mentioned earlier.