WordPress in root folder and vBulletin in subfolder

Question

I installed WordPress in my host root folder and I installed vBulletin in a subfolder. I changed my WordPress default permalink to "postname".

Now when I want to open forum (the vBulletin subfolder), it redirects to root folder (WordPress) and gives "not found post".

When I delete .htaccess file in the root folder (WordPress), the subfolder works fine, but accessing WordPress posts gives 404 error.

How can I solve this problem?

It is my WordPress .htaccess file:

# 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

And this is the subfolder (vBulletin) .htaccess file:

# Comment the following line (add '#' at the beginning)
# to disable mod_rewrite functions.
# Please note: you still need to disable the hack in
# the vBSEO control panel to stop url rewrites.
RewriteEngine on

# Some servers require the Rewritebase directive to be
# enabled (remove '#' at the beginning to activate)
# Please note: when enabled, you must include the path
# to your root vB folder (i.e. RewriteBase /forums/)
#RewriteBase /

RewriteCond %{HTTP_HOST} !^soft-game\.ir
RewriteRule (.*) http://soft-game.ir/forums/$1 [L,R=301]

RewriteRule ^((urllist|sitemap_).*\.(xml|txt)(\.gz)?)$ vbseo_sitemap/vbseo_getsitemap.php?sitemap=$1 [L]

RewriteCond %{REQUEST_URI} !(admincp/|modcp/|cron|vbseo_sitemap|api\.php)
RewriteRule ^((archive/)?(.*\.php(/.*)?))$ vbseo.php [L,QSA]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !/(admincp|modcp|clientscript|cpstyles|images)/
RewriteRule ^(.+)$ vbseo.php [L,QSA]

Answer 1

You should install wordpress and vBulletin in seperate folders, because a sub-folder in the wordpress insallation means that it is part of wordpress, and it will not act as an unique entity.

Create two folders, name first as 'blogs' or whatever for wordpress and create another folder in the root and name it 'forums' or whatever you like for vBulletin only then the 404 error from wordpress will disappear.