opportunity close pre event plugin.

Hi All,

I want to be able to stop an opportunity from being closed as 'won' if the user does not have a specific role (e.g. only certain users can actually close an opportunity as 'won'). I have tried to create a plugin registered on the pre-stage, parent pipeline on the create of an opportunity close. it then checks if the users have the required roles and throws an error message if they dont (effectively stopping the opp from closing) or does nothing and lets it continue as normal. However it doesn't seem to be triggering at all. it doesnt even output simple debug message to a text file, which implies that it isn' t actually triggering the plugin :-(have i simply registered the plugin incorrectly?

any help is appreciated!

Thanks!