If you are getting this error then it may be malware script that is attached to your site. Kindly scan your PC, most probably your PC is compromised.
In 99% cases, clients PC is compromised. Never save password in your PC or in FTP Software.
Read :
http://www.google.com/support/webmasters/bin/answer.py?answer=163633
Solution :
Google appeal : http://www.google.com/support/webmasters/bin/answer.py?answer=168328
In 99% cases, clients PC is compromised. Never save password in your PC or in FTP Software.
Read :
http://www.google.com/support/webmasters/bin/answer.py?answer=163633
Google Search Help
www.google.com
Solution :
- Change all the passwords.
- Reupload the malware FREE files from another PC.
- Check your site to make sure you don't have any vulnerable PHP scripts installed like an out of date Word Press, Joomla, or something else that could compromise your account. Update all 3rd party application.
- After uploading the malware FREE site, again change your FTP & control panel password.
Google appeal : http://www.google.com/support/webmasters/bin/answer.py?answer=168328