When try to register on my site can't type the reCAPTCHA correctly.

Hi.
When I try to register a new site on my netvork, I get this message when try to type the reCAPTCHA: The reCAPTCHA wasn't entered correctly. Please try again.
I have tryed a 1000 times but get the same message.
Are there some settings I have missed or what?

Best Tim