I am not sure whether this is exactly fear of success. I think it may be fear of failure, or more specifically fear of discovering that one does not have talent.

For example, take somebody that is smart, is a great conservationist in parties, makes great jokes and has read the entire literary cannons of several countries. All his friends say he should be a writer. He has always dreamed of being a writer. Yet he never starts writing. Is that fear of success? Or fear of trying and discovering that despite everything he did not have talent?

Anyway, while we are on the subject linked below is a hilarious episode of Black Books that is about this. BTW I think the main character of that show is someone like the person in my example.

http://www.hulu.com/watch/114471/black-books-elephants-and-h...