Captcha Verification Code Not Working

Hi

I'm currently testing my Zoho Contact Form on my blog however it seems that the captcha verification code is not working. Everytime I try to submit a form the following msg appears: "Please enter the correct verification code.". I have tried the form on both FF and IE with similar negative results. I am also entering the code in caps. Hope someone out there can give some advice on what is the problem

Thanks!