Sorry that my experience is also limited. May be the shader is too complicated for your video card ? Have you tried the Ogre Ocean demo program on your machine ?
On top of the Orge ocean shader, I have added quite a number of parameters and I am not sure if it create a burden on it. I also passed the reflection plane to it for it to select a cubemap or reflection plane on the fly. And also, I added a debug colorplane on it. I believe it might create problems.
If you can run the Ogre demo well on your machine, I will reduce the shader program to match the Ogre one and see if it help.