WordPress sections in htaccess kills FrontPage permissions

To make sure WordPress catches requests to your blog only you have to restrict the rewrite rules to your domain (host) name.

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
# must match exactly your domain name
RewriteCond %{HTTP_HOST} ^example\.com$
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

And some of your .htaccess directives look a little bit … strange. You don’t need IndexIgnore if you forbid index listings with Options -Indexes.
RewriteEngine On should be called just once.