Spencer Bryant

Sorry about not elaborating on the $base variable. You are correct in that the plugin does not reference it; however, that is the problem. WordPress uses the variable when creating new blogs for a site. $base is defined in wp-config by default when you enable multisites. But since your plugin allows multiple sites, it needs to update that variable for each site. I noticed the issue when creating sites whose domain/path were a child of another site’s domain/path. The fix is really simple:

function set_base_var() {
global $base;

if ( !is_multisite() )
return;

$base = get_current_site()->path;
}

add_action( 'muplugins_loaded', 'set_base_var');

It may be better to use a different action hook, but this one seems to work just fine.

As for the .htaccess file, it is a pretty simple adjustment as well. All it does is allow the rewrite rules to handle urls to nested sites.

RewriteEngine On
RewriteBase /

# Rule 1
RewriteRule ^index\.php$ - [L]

# Rule 2: uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)*files/(.+) wp-includes/ms-files.php?file=$2 [L]

# Rule 3: add a trailing slash to "/wp-admin"
# Note: This rule issues and redirect that will subsequently match Rule 5
RewriteRule ^(([_0-9a-zA-Z-]+/)*)wp-admin$ $1wp-admin/ [R=301,L]

# Rule 4: do nothing if URL is a file or directory
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]

# Rule 5: strip preceeding path from wp-(content|admin|includes) paths
# Example: {RewriteBase}sub-site/sub-folder/wp-admin/sites.php --> {RewriteBase}wp-admin/sites.php
RewriteRule ^([_0-9a-zA-Z-]+/)*(wp-(content|admin|includes).*) $2 [L]

# Rule 6
RewriteRule ^([_0-9a-zA-Z-]+/)*(.*\.php)$ $2 [L]

# Rule 7
RewriteRule . index.php [L]

My email is (hopefully): s z b 0 0 1 8 @ a u b u r n . e d u

I did a fresh install of WordPress, and everything started working just fine. So it was probably a problem with theme or another plugin.