Why are certain fonts not loading in my fontbook

I am having issues loading fonts into my fontbook - and onto my system.

Oddly, one of these fonts is Helvetica.

I am running on Mac OSX 10.7.5 - Intel Core i5.

Version of fontbook: Version 198.4 (198)

If anyone has any ideas of why this is happening, and what I need to do, please let me know!! 🙂

Thanks