I'm trying to install and run rviz on Ubuntu 10.04, but not having much success.

I've made the package successfully using

    rosmake --rosdep-install rviz

but when trying to run it using

    rosrun rviz rviz

I get the following error:

Failed to initialize Ogre: OGRE EXCEPTION(7:InternalErrorException):
Could not load dynamic library Plugin_CgProgramManager.  System Error:
Plugin_CgProgramManager.so: cannot open shared object file: No such
file or directory in DynLib::load at OgreDynLib.cpp (line 81)

Any idea what this means?