On the gazebo side, major changes from Electric simulator_gazebo (pre gazebo-1.0.0-RC) to the Fuerte version (gazebo-1.0.0-RCX) can be found on the gazebo change list wiki page. Notably, the new Gazebo plugins have been redesigned to be more flexible to the end-users, but unfortunately, this means the new plugin API is not backwards compatible with the old version. To convert old style plugins to the 1.0.0-RC plugin, please take a quick look at the plugin tutorials, in particular, this tutorial tries to provide an overview on the conversion process. For additional reference, you can also take a look at the updates in gazebo_plugins and pr2_gazebo_plugins packages. For questions or troubleshooting the conversion process, please make use of answers or the gazebo mailing list.