Yeah, I had it. You need to need to remove any Safari plug-ins you have. Spotlight "SIMBL" and open the folder with that name. If you have any plug-ins such as Acid Search, Pith Helmet, etc, get rid of them.
If this isn't the case (and it wasn't with me) you need to reinstall Safari, which hadn't updated properly on my machine. To do that, you need to get an app called Pacifist (Google it) and extract the Safari installer from there.
If you need more detailed explanations, say and I'll post them - in a rush now though.