Restricting RewriteRule to ignore certain folders - .htaccess

Question

I have a basic Rewrite rule defined in the root of my website, in an .htaccess file:
<IfModule mod_rewrite.c>
# http://www.generateit.net/mod-rewrite/index.php
# Tell PHP that the mod_rewrite module is ENABLED.
SetEnv HTTP_MOD_REWRITE On
RewriteEngine on
RewriteRule ^([^/]*)/$ category.php?cat=$1 [L]
RewriteRule ^([^/]*)/([^/]*)/$ post.php?cat=$1&post=$2 [L]
RewriteRule ^blog-([^/]*).php$ default.php?page=$1 [L]
</IfModule>
I have 2 sites hosted on the same folder structure:
DIR: example2.com
file: category.php
file: default.php
file: post.php
So the rewrite rule will redirect e.g.
example.com/post.php?cat=general-ledger&post=gl-journals-volumes
to:
example.com/general-ledger/gl-journals-volumes/
However, I have installed Wordpress in a folder called ddc on example2, but when I visit:
example2.com/ddc/wp-admin/user/
I can't view it, as the system thinks it's trying to view a rewritten page.
Is there any way I can stop the rewrite rule from firing for specific directories?
I have tried:
RewriteCond %{REQUEST_URI} !^/(example2.com|ddc)/?(.*)$ [NC]
But it made no difference. Furthermore, the error log shows this when I try to access the folder:
[Mon Jan 16 22:39:53.365334 2017] [autoindex:error] [pid 28997]
[client my_ip_address_here:53652] AH01276: Cannot serve directory
/home/oracle36/public_html/example2.com/ddc/wp-admin/user/: No
matching DirectoryIndex (default.php) found, and server-generated
directory index forbidden by Options directive

Answer 1

Your rewrite rules are not the problem. They only affect URLs with directories of one or two levels. Your problem is that you don't have index.php set up as a directory index, so there is nothing for Apache to serve from the WordPress directory. Add this to your .htaccess:
DirectoryIndex default.php index.php
I am adding default.php to that because the error message shows you have that set up already, and then adding index.php to it as another option, to support WordPress. You can remove your RewriteCond.