Why is my simulated bumper not working?

I have checked out multiple sources for simulated bumpers in Gazebo and I tried a lot of them. I tried to copy stuff from a lot of models into mine and tried to hook it up but it won't work and gazebo is crashing most of the time or it does not post any topic. Could somebody please tell me what is wrong with this piece of code? (URDF model) Thanks! true30.0bumper0_collisionbumper0_topicbumper0_frame What I get: > [INFO] [WallTime: 1424980069.535978] [0.043000] Calling service /gazebo/spawn_urdf_model ***** Internal Program Error - assertion (this->customContactPublishers.count(name) > 0) failed in std::string gazebo::physics::ContactManager::CreateFilter(const string&, const std::vector>&): /tmp/buildd/gazebo2-2.2.3/gazebo/physics/ContactManager.cc(329): Failed to create a custom filter Aborted (core dumped) Service call failed: transport error completing service call: unable to receive data from sender, check sender's logs for details