If you see this error when trying to load the Rhino Plug-in, can you please verify / test the following:
Which version of Windows are you using(I think this is limited to Vista and Win7)
Close all open Rhinos
Right click on RenderOctane.rhp and select properties
In the properties, do you see an "Unblock" button?
If you click the Unblock button, then start Rhino and try to load the plug-in, so you continue to see this error?
One of the theories is that Windows is applying security flags to the rhp because it was downloaded from the internet and is therefore "untrusted". The Rhino developers are aware of this issue and are discussing it, but it would be great if people who are having issues could check the "unblock" theory to see if it holds water.
Thanks,
Sam