It may also be that the certificate being used is not for the Fully Qualified Domain Name, check again using 'View Certificates' to see if the domain name on the certificate matches the domain name in the URL that you are going to.
Check your Internet Option' and make sure that 'Use SSL 3.0' is ticked in the 'Advanced' section.
See Also:
Why does the secure part of the website say the name on the security certificate is invalid or does not match the name of the site?