Index: wp-admin/includes/htaccess.ms
===================================================================
--- wp-admin/includes/htaccess.ms	(revision 12962)
+++ wp-admin/includes/htaccess.ms	(working copy)
@@ -2,18 +2,14 @@
 RewriteBase BASE/
 
 #uploaded files
-RewriteRule ^(.*/)?files/$ index.php [L]
-RewriteCond %{REQUEST_URI} !.*wp-content/plugins.*
-RewriteRule ^(.*/)?files/(.*) wp-includes/ms-files.php?file=$2 [L]
+RewriteRule ^([^/]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]
 
 # add a trailing slash to /wp-admin
-RewriteCond %{REQUEST_URI} ^.*/wp-admin$
-RewriteRule ^(.+)$ $1/ [R=301,L]
+RewriteRule ^([^/]+/)?wp-admin$ $1wp-admin/ [R=301,L]
 
 RewriteCond %{REQUEST_FILENAME} -f [OR]
 RewriteCond %{REQUEST_FILENAME} -d
 RewriteRule . - [L]
-RewriteRule  ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
-RewriteRule  ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
-RewriteRule . index.php [L]
-
+RewriteRule  ^([^/]+/)?(wp-(content|admin|includes).*) $2 [L]
+RewriteRule  ^([^/]+/)?(.*\.php)$ $2 [L]
+RewriteRule . index.php [L]
\ No newline at end of file