I replicated this without logging in (http://www.connectvonnect.com/terms-of-use-agreement/) had page not found when I loaded it.
Do you have any login plugins on your site? Often wordpress glitches can be caused by conflicting plugins, to troubleshoot this simply disable all plugins and re-enable one at a time and check if the error persists. If you troubleshoot your plugins down to a plugin conflict you can contact the plugin author with the issue, as they will know their code best.
Without much more information about your site I can only recommend checking your .htaccess file, and checking if the problem persists with permalinks turned off?