I have been having this problem too. That specific error comes up in Google’s Chrome browser, in IE it will just say HTTP 505 or will simply not render.
My host asked me to change ‘localhost’ in wp-config.php to a different value, that successfully had my blog display again (https://verabear.net) but it reverted to the 2.6 version of WP. Before the error, I was using 2.7, and have put up several posts. They are gone!
Does anyone have any idea on what can be done here?