.htaccess conflict with Wordpress

[Dezio]

Hello,
I installed wordpress and vbullettin forum.
wordpress on /.
vbullettin on /forum
If I try to visit http://www.domain.com/forum all work, but if I try to visit http://www.domain.com/forum/topic I've a 404 error.
his is my .htaccess file:
Code:

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

Can anyone help me?
Regards

[Dezio]

I got this error if I select

Mod Rewrite Friendly URLs

under "Friendly URLs".
Is there an .htaccess file under vbulletin folders?

[Lynne]

If you are using Mod Rewrite Friendly URLs then you need to upload the .htaccess from the do_not_upload/rewrite directory.

[Dezio]

Ahh which one?
This one?

apache2/forum/.htaccess?

Im lost about 20 hours to resolve this issue by modifing wordpress .htaccess without success..

[Lynne]

The one in /apache2 . You would only use the others if you hav stub directories. You may need to also add a RewriteBase to your .htaccess to the wordpress one doesn't cause issues.

[Dezio]

Ok, I copy the .htaccess from do_not_upload/rewrite/apache2/forum/.htaccess to the /forum/ directory on the server.
I also edited the main .htaccess of wordpress on ./ like this:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

RewriteCond %{REQUEST_URI} !^/(forum|forum/.*)$

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

but I've the same problem :/

--------------- Added [DATE]1372703151[/DATE] at [TIME]1372703151[/TIME] ---------------

Ok, found solution:

# If you are having problems or are using VirtualDocumentRoot, uncomment this line and set 

it to your forum component directory.
RewriteBase /forum/