Older version of protoc which is incompatible with your Protocol Buffer headers

I'm trying to install gazebo_ros_pkgs on ROS Indigo with the debian version of Gazebo 2.2. However, I'm getting lots of error due to mismatched protobuf header versions:> This file was generated by an older version of protoc which is incompatible with your Protocol Buffer headers I'm using libprotobuf 2.5.0-9, the latest in Ubuntu 14.04. I've googled and tried lots of things but can't get the versions to match. Any insights on how to do this without installing Gazebo from source? Thanks!