I did what you suggested and the problem persists. Here's my .htaccess:
ErrorDocument 401 /error.php?error=401
ErrorDocument 402 /error.php?error=402
ErrorDocument 403 /error.php?error=403
ErrorDocument 404 /error.php?error=404
ErrorDocument 500 /error.php?error=500
php_flag safe_mode off
php_flag register_globals on
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^.*$ - [S=75]
RewriteRule ^(about/mc-stats-page)/trackback/?$ /index.php?pagename=$1&tb=1 [QSA,L]
RewriteRule ^(about/mc-stats-page)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(about/mc-stats-page)/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(about/mc-stats-page)/page/?([0-9]{1,})/?$ /index.php?pagename=$1&paged=$2 [QSA,L]
RewriteRule ^(about/mc-stats-page)(/[0-9]+)?/?$ /index.php?pagename=$1&page=$2 [QSA,L]
RewriteRule ^(about/plugins)/trackback/?$ /index.php?pagename=$1&tb=1 [QSA,L]
RewriteRule ^(about/plugins)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(about/plugins)/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(about/plugins)/page/?([0-9]{1,})/?$ /index.php?pagename=$1&paged=$2 [QSA,L]
RewriteRule ^(about/plugins)(/[0-9]+)?/?$ /index.php?pagename=$1&page=$2 [QSA,L]
RewriteRule ^(about/contact-us)/trackback/?$ /index.php?pagename=$1&tb=1 [QSA,L]
RewriteRule ^(about/contact-us)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(about/contact-us)/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(about/contact-us)/page/?([0-9]{1,})/?$ /index.php?pagename=$1&paged=$2 [QSA,L]
RewriteRule ^(about/contact-us)(/[0-9]+)?/?$ /index.php?pagename=$1&page=$2 [QSA,L]
RewriteRule ^(about/heatmap)/trackback/?$ /index.php?pagename=$1&tb=1 [QSA,L]
RewriteRule ^(about/heatmap)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(about/heatmap)/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(about/heatmap)/page/?([0-9]{1,})/?$ /index.php?pagename=$1&paged=$2 [QSA,L]
RewriteRule ^(about/heatmap)(/[0-9]+)?/?$ /index.php?pagename=$1&page=$2 [QSA,L]
RewriteRule ^(web-links-page)/trackback/?$ /index.php?pagename=$1&tb=1 [QSA,L]
RewriteRule ^(web-links-page)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(web-links-page)/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(web-links-page)/page/?([0-9]{1,})/?$ /index.php?pagename=$1&paged=$2 [QSA,L]
RewriteRule ^(web-links-page)(/[0-9]+)?/?$ /index.php?pagename=$1&page=$2 [QSA,L]
RewriteRule ^(archives)/trackback/?$ /index.php?pagename=$1&tb=1 [QSA,L]
RewriteRule ^(archives)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(archives)/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(archives)/page/?([0-9]{1,})/?$ /index.php?pagename=$1&paged=$2 [QSA,L]
RewriteRule ^(archives)(/[0-9]+)?/?$ /index.php?pagename=$1&page=$2 [QSA,L]
RewriteRule ^(smartarchives)/trackback/?$ /index.php?pagename=$1&tb=1 [QSA,L]
RewriteRule ^(smartarchives)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(smartarchives)/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(smartarchives)/page/?([0-9]{1,})/?$ /index.php?pagename=$1&paged=$2 [QSA,L]
RewriteRule ^(smartarchives)(/[0-9]+)?/?$ /index.php?pagename=$1&page=$2 [QSA,L]
RewriteRule ^(about)/trackback/?$ /index.php?pagename=$1&tb=1 [QSA,L]
RewriteRule ^(about)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(about)/(feed|rdf|rss|rss2|atom)/?$ /index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^(about)/page/?([0-9]{1,})/?$ /index.php?pagename=$1&paged=$2 [QSA,L]
RewriteRule ^(about)(/[0-9]+)?/?$ /index.php?pagename=$1&page=$2 [QSA,L]
RewriteRule ^feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?&feed=$1 [QSA,L]
RewriteRule ^(feed|rdf|rss|rss2|atom)/?$ /index.php?&feed=$1 [QSA,L]
RewriteRule ^page/?([0-9]{1,})/?$ /index.php?&paged=$1 [QSA,L]
RewriteRule ^comments/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?&feed=$1&withcomments=1 [QSA,L]
RewriteRule ^comments/(feed|rdf|rss|rss2|atom)/?$ /index.php?&feed=$1&withcomments=1 [QSA,L]
RewriteRule ^comments/page/?([0-9]{1,})/?$ /index.php?&paged=$1 [QSA,L]
RewriteRule ^search/(.+)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?s=$1&feed=$2 [QSA,L]
RewriteRule ^search/(.+)/(feed|rdf|rss|rss2|atom)/?$ /index.php?s=$1&feed=$2 [QSA,L]
RewriteRule ^search/(.+)/page/?([0-9]{1,})/?$ /index.php?s=$1&paged=$2 [QSA,L]
RewriteRule ^search/(.+)/?$ /index.php?s=$1 [QSA,L]
RewriteRule ^category/(.+)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?category_name=$1&feed=$2 [QSA,L]
RewriteRule ^category/(.+)/(feed|rdf|rss|rss2|atom)/?$ /index.php?category_name=$1&feed=$2 [QSA,L]
RewriteRule ^category/(.+)/page/?([0-9]{1,})/?$ /index.php?category_name=$1&paged=$2 [QSA,L]
RewriteRule ^category/(.+)/?$ /index.php?category_name=$1 [QSA,L]
RewriteRule ^author/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?author_name=$1&feed=$2 [QSA,L]
RewriteRule ^author/([^/]+)/(feed|rdf|rss|rss2|atom)/?$ /index.php?author_name=$1&feed=$2 [QSA,L]
RewriteRule ^author/([^/]+)/page/?([0-9]{1,})/?$ /index.php?author_name=$1&paged=$2 [QSA,L]
RewriteRule ^author/([^/]+)/?$ /index.php?author_name=$1 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?year=$1&monthnum=$2&day=$3&feed=$4 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/(feed|rdf|rss|rss2|atom)/?$ /index.php?year=$1&monthnum=$2&day=$3&feed=$4 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/page/?([0-9]{1,})/?$ /index.php?year=$1&monthnum=$2&day=$3&paged=$4 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/?$ /index.php?year=$1&monthnum=$2&day=$3 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?year=$1&monthnum=$2&feed=$3 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/(feed|rdf|rss|rss2|atom)/?$ /index.php?year=$1&monthnum=$2&feed=$3 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/page/?([0-9]{1,})/?$ /index.php?year=$1&monthnum=$2&paged=$3 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/?$ /index.php?year=$1&monthnum=$2 [QSA,L]
RewriteRule ^([0-9]{4})/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?year=$1&feed=$2 [QSA,L]
RewriteRule ^([0-9]{4})/(feed|rdf|rss|rss2|atom)/?$ /index.php?year=$1&feed=$2 [QSA,L]
RewriteRule ^([0-9]{4})/page/?([0-9]{1,})/?$ /index.php?year=$1&paged=$2 [QSA,L]
RewriteRule ^([0-9]{4})/?$ /index.php?year=$1 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/([^/]+)/trackback/?$ /index.php?year=$1&monthnum=$2&day=$3&name=$4&tb=1 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$ /index.php?year=$1&monthnum=$2&day=$3&name=$4&feed=$5 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/([^/]+)/(feed|rdf|rss|rss2|atom)/?$ /index.php?year=$1&monthnum=$2&day=$3&name=$4&feed=$5 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/([^/]+)/page/?([0-9]{1,})/?$ /index.php?year=$1&monthnum=$2&day=$3&name=$4&paged=$5 [QSA,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/([^/]+)(/[0-9]+)?/?$ /index.php?year=$1&monthnum=$2&day=$3&name=$4&page=$5 [QSA,L]
</IfModule>
# END WordPress
(AND on another topic... can someone provide pointers for how I could configure my Linux server (Fedora Core 4) running Apache/MySQL/PHP not to need "index.php" in my permalinks?)