If your website is showing a malware / forgery / phishing warning this indicates that your website has been exploited by a hacker and inserted code into your website pages. You will need to get your website designer/developer to check your website for this code and remove it.
For more information on how to manage this read Google's guidelines here: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=163633
Once you have removed the malware you will need to resubmit your site to Google for review. See our 'Request a malware review' article here: 'Requesting a malware review'
