Captcha problems

I'm having trouble with the captcha on 4chan, regardless of what board im on. It tells me that i've typed it wrong but i clearly havent.

Anyone having the same problem or have a way around this? its getting pretty annoying..

Much appreciated.

I've tried using Chrome, Firefox and IE. My main is Safari and that doesnt work either. I'm using a mac btw, not sure if that changes anything. but yeah? :S