Undefined index: host

Below is the error dump I get when I go to my vanilla page on my home machine (i.e. http://localhost/xcvanilla/). I am using SSO. The installation was without errors. My thought is that there is no assigned value for $Host. This isn't a terribly brilliant theory, since on the SSO configuration page there is no value assigned to the Vanilla Cookie Domain property. That form field does not allow input so I can't add it. When I installed Vanilla I used "localhost" as my domain, but it doesn't appear to have been saved.

Do you think this is really the problem and is there a way to insert "localhost" as the domain?

Mike

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Fatal Error in PHP.ErrorHandler();
Undefined index: host

The error occurred on or near: C:\webs\html\xcvanilla\library\core\class.handshakeauthenticator.php
88: if(is_array($this->_HandshakeData))
89: return $this->_HandshakeData;
90:
91: $UrlParts = parse_url($this->AuthenticateUrl);
92: $Host = $UrlParts['host']; *****highlighted*******
93: $Port = ArrayValue('port', $UrlParts, '80');
94: $Path = $UrlParts['path'];
95: $Referer = Gdn_Url::WebRoot(TRUE);
96: $Query = ArrayValue('query', $UrlParts, '');
Backtrace:
[C:\webs\html\xcvanilla\library\core\functions.error.php:124] PHP::include();
[C:\webs\html\xcvanilla\library\core\class.handshakeauthenticator.php:92] PHP::ErrorHandler();
[C:\webs\html\xcvanilla\library\core\class.handshakeauthenticator.php:172] Gdn_HandshakeAuthenticator->GetHandshakeData();
[C:\webs\html\xcvanilla\library\core\class.session.php:225] Gdn_HandshakeAuthenticator->GetIdentity();
[C:\webs\html\xcvanilla\index.php:30] Gdn_Session->Start();