Index.php does not redirect to Main_Page

Hello,

I recently upgraded from MediaWiki 1.1.0 to MediaWiki
1.4.0 and also migrated from Windows to Linux.  The
upgrade appears to have worked, but I do not see
anything when I request index.php.

The following URL yields "page could not be displayed"
in the browser:
http://<myserver>/wiki/index.php

The corresponding entry in Apache's access_log shows:
[29/Mar/2005:11:16:34 -0800] "GET /wiki/index.php
HTTP/1.1" 301 -

My LocalSettings.php includes these settings:
$wgScriptPath       = "/wiki";
$wgScript           = "$wgScriptPath/index.php";
$wgRedirectScript   = "$wgScriptPath/redirect.php";
[...]
$wgArticlePath      = "$wgScript/$1";

Note that specifying the article name explicitly in
the URL *does* work:
http://<myserver>/wiki/index.php/Main_Page

Does anyone have any ideas about how I can get the
index.php to show the Main_Page automatically?

Thanks for your help!
-Amy
chanamy1-rphTv4pjVZMJGwgDXS7ZQA@xxxxxxxxxxxxxxxx