That second line scares the pants off me!
Is that just a pointer or is there something wrong.
# BEGIN s9y
ErrorDocument 404 /serendipity/index.php
DirectoryIndex /serendipity/index.php
RewriteEngine On
RewriteBase /serendipity/
RewriteRule ^(archives/([0-9]+)-[0-9a-z\.\_!;,\+\-]+\.html) index.php?/$1 [NC,L,QSA]
RewriteRule ^(authors/([0-9]+)-[0-9a-z\.\_!;,\+\-]+) index.php?/$1 [NC,L,QSA]
RewriteRule ^(feeds/categories/([0-9;]+)-[0-9a-z\.\_!;,\+\-]+\.rss) index.php?/$1 [NC,L,QSA]
RewriteRule ^(feeds/authors/([0-9]+)-[0-9a-z\.\_!;,\+\-]+\.rss) index.php?/$1 [NC,L,QSA]
RewriteRule ^(categories/([0-9;]+)-[0-9a-z\.\_!;,\+\-]+) index.php?/$1 [NC,L,QSA]
RewriteRule ^archives([/A-Za-z0-9]+)\.html index.php?url=/archives/$1.html [NC,L,QSA]
RewriteRule ^([0-9]+)[_\-][0-9a-z_\-]*\.html index.php?url=$1-article.html [L,NC,QSA]
RewriteRule ^feeds/(.*) index.php?url=/feeds/$1 [L,QSA]
RewriteRule ^unsubscribe/(.*)/([0-9]+) index.php?url=/unsubscribe/$1/$2 [L,QSA]
RewriteRule ^approve/(.*)/(.*)/([0-9]+) index.php?url=approve/$1/$2/$3 [L,QSA]
RewriteRule ^delete/(.*)/(.*)/([0-9]+) index.php?url=delete/$1/$2/$3 [L,QSA]
RewriteRule ^(admin|entries)(/.+)? index.php?url=admin/ [L,QSA]
RewriteRule ^archive/? index.php?url=/archive [L,QSA]
RewriteRule ^(index|atom[0-9]*|rss|b2rss|b2rdf).(rss|rdf|rss2|xml) rss.php?file=$1&ext=$2
RewriteRule ^(plugin|plugin)/(.*) index.php?url=$1/$2 [L,QSA]
RewriteRule ^search/(.*) index.php?url=/search/$1 [L,QSA]
RewriteRule ^(serendipity\.css|serendipity_admin\.css) index.php?url=/$1 [L,QSA]
RewriteRule ^index\.(html?|php.+) index.php?url=index.html [L,QSA]
RewriteRule ^htmlarea/(.*) htmlarea/$1 [L,QSA]
RewriteRule (.*\.html?) index.php?url=/$1 [L,QSA]
<Files *.tpl.php>
deny from all
</Files>
<Files *.tpl>
deny from all
</Files>
<Files *.sql>
deny from all
</Files>
<Files *.inc.php>
deny from all
</Files>
<Files *.db>
deny from all
</Files>
# END s9y