Thanks very much for the response.
That is just one of the sections where I encountered that problem. I have also tried installing in block section it was the same problem I encountered.
I have not been able to install any plugin whether self developed or downloaded plugin.
i tried installing from a plugin which is available online, it was the same result it was not active and I could not activate it either in the block or report categories or section.
This is the modification to earlier response 30 minutes passed before i could make modification to the response