phpBB forum error 500 internal

I'm getting a strange error message when going into forum posts. This is what it says:

http://www.edu-hq.com/forum/topic41.html

What is happening? How do I fix it?

 

I get a 404 not found here. I see you did a SE friendly URL hack. Which one did you use? Can you check your .htaccess file and see if something is missing.

 

I used the phpBB SEO mod.

Here's my .htaccess file:

RewriteEngine On 
RewriteCond %{HTTP_HOST} ^edu-hq.com$ [NC] RewriteRule ^(.*)$ http://www.edu-hq.com/$1 [R=301,L] 

Options +FollowSymlinks 
RewriteEngine On 
RewriteBase / 

# FORUM PROTECTION RULE 
RewriteRule ^forum/.+/([^/]+\.html)$ /forum/index.php [R=301,L] 
# CATEGORIES 
RewriteRule ^forum/.+-vc([0-9]+)\.html$ /forum/index.php?c=$1 [QSA,L] 
# PAGINATED FORUM 
RewriteRule ^forum/.+-vf([0-9]+)-([0-9]+)\.html$ /forum/viewforum.php?f=$1&start=$2 [QSA,L] 
# FORUM 
RewriteRule ^forum/.+-vf([0-9]+)\.html$ /forum/viewforum.php?f=$1 [QSA,L] 
# PAGINATED TOPIC 
RewriteRule ^forum/.+-vt([0-9]+)-([0-9]+)\.html$ /forum/viewtopic.php?t=$1&start=$2 [QSA,L] 
# TOPIC 
RewriteRule ^forum/.+-vt([0-9]+)\.html$ /forum/viewtopic.php?t=$1 [QSA,L] 
# POST 
RewriteRule ^forum/post([0-9]+)\.html$ /forum/viewtopic.php?p=$1 [QSA,L] 
#PROFILES 
RewriteRule ^forum/member([0-9]+)\.html$ /forum/profile.php?mode=viewprofile&u=$1 [QSA,L] 

# BEGIN WordPress 
<IfModule mod_rewrite.c> 
RewriteEngine On 
RewriteBase / 
RewriteCond %{REQUEST_FILENAME} !-f 
RewriteCond %{REQUEST_FILENAME} !-d 
RewriteRule . /index.php [L] 
</IfModule> 

# END WordPress 

Code (markup):

Basically this is what I'd like to happen. If people type in http://edu-hq.com they get sent to http://www.edu-hq.com which acts as the homepage. From there I'd like three sub directories like below:

http://www.edu-hq.com
/blog
/forum
/directory

How do I set up .htaccess to make this all happen as well as work with the forum rewrite rule?
This is soooo frustrating at the moment!!

 

OK a couple of quick questions :

Does the forum work when you have only the forum rewrite rules in htaccess ?

Did you do the hack step by step ?

EDIT : Actually http://www.edu-hq.com/forum/mathematics-vf11.html works and http://www.edu-hq.com/forum/topic8.html redirects me to Wordpress so it's the htaccess.
Start like this : make the forum work. do the www. redirect and test if the forum works (should work) and then the Wordpress one so you can see what breaks it.