Welcome, James! You might want to ask a mod to move this to the main "Building your own stompbox" area of the forum (or just re-post) - there's far more passing traffic there. (This section is for the forum "beginner project", and there's hardly any footfall here.)
You'll also find a very handy, sticky "Debugging" thread when you get there. Follow the instructions and post your findings - it really works: we'll definitely get you sorted!
