[pityocamptes]

Here is how I did mine, they had to be the first thing in the file, I had the same issue...

<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>

RewriteEngine on
RewriteBase /

RewriteCond %{HTTP_HOST} !^www.XXXXXXXXXXXXXXXX.com$ [NC]
RewriteRule ^(.*)$ https://www.XXXXXXXXXXXXXX.com/$1 [R=301,L]

RewriteEngine on
RewriteBase /

RewriteCond %{SERVER_PORT} !443
RewriteRule (.*) https://www.XXXXXXXXXXXXXX.com [R=301,L]

# This file is only needed if you have set the Forum Component URL in your admincp and you are 
# using the mod_rewrite option for friendly urls.  If this is the case, copy this file
# to your forum component stub directory.

# If you are having problems or are using VirtualDocumentRoot, uncomment this line and set it to your forum component directory.
# RewriteBase /forum-stub-directory/

# If you are having problems with the rewrite from content/ to content.php, uncomment this line to turn MultiViews off.

Options -MultiViews

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -l [OR]
RewriteCond %{REQUEST_FILENAME} -d

RewriteRule ^.*$ - [NC,L]

# Forum
RewriteRule ^threads/.* showthread.php [QSA]
RewriteRule ^forums/.* forumdisplay.php [QSA]
RewriteRule ^members/.* member.php [QSA]
RewriteRule ^blogs/.* blog.php [QSA]
RewriteRule ^entries/.* entry.php [QSA]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -l [OR]
RewriteCond %{REQUEST_FILENAME} -d

RewriteRule ^.*$ - [NC,L]

# MVC
RewriteRule ^(?:(.*?)(?:/|$))(.*|$)$ $1.php?r=$2 [QSA]

# Check MVC result
RewriteCond %{REQUEST_FILENAME} -f
RewriteRule ^(.*)$ - [NC,L]
RewriteRule ^(.*)$ - [R=404,L]

# FeedBurner
RewriteCond %{HTTP_USER_AGENT} !FeedBurner [NC]