The current version of FastCheck is 2.0.0.4. If FastCheck keeps telling you that a new version is available, or if the version in the About box is not 2.0.0.4, clear your browser cache and try to download FastCheck again.
Also, to work around most browser (and ISP 'transparent') caches, I have now included the version number in both executables.
You can use FastTest to test your connection to FastMail.FM.