htaccess rule doesn't working? - php

Question

htaccess rule for subfolder
Options +Includes
<ifmodule mod_deflate.c>
AddOutputFilterByType DEFLATE text/text text/html text/plain text/xml text/css application/x-javascript application/javascript
BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4\.0[678] no-gzip
BrowserMatch \bMSIE !no-gzip !gzip-only-text/html
</ifmodule>
# Expires Headers - 2678400s = 31 days
<ifmodule mod_expires.c>
ExpiresActive On
ExpiresDefault "access plus 1 seconds"
ExpiresByType text/html "access plus 7200 seconds"
ExpiresByType image/gif "access plus 2678400 seconds"
ExpiresByType image/jpeg "access plus 2678400 seconds"
ExpiresByType image/png "access plus 2678400 seconds"
ExpiresByType text/css "access plus 518400 seconds"
ExpiresByType text/javascript "access plus 2678400 seconds"
ExpiresByType application/x-javascript "access plus 2678400 seconds"
</ifmodule>
# Cache Headers
<ifmodule mod_headers.c>
# Cache specified files for 31 days
<filesmatch "\.(ico|flv|jpg|jpeg|png|gif|css|swf)$">
Header set Cache-Control "max-age=2678400, public"
</filesmatch>
# Cache HTML files for a couple hours
<filesmatch "\.(html|htm)$">
Header set Cache-Control "max-age=7200, private, must-revalidate"
</filesmatch>
# Cache PDFs for a day
<filesmatch "\.(pdf)$">
Header set Cache-Control "max-age=86400, public"
</filesmatch>
# Cache Javascripts for 31 days
<filesmatch "\.(js)$">
Header set Cache-Control "max-age=2678400, private"
</filesmatch>
</ifmodule>
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC]
RewriteRule ^(.*)$ http://%1%{REQUEST_URI} [R=301,QSA,NC,L]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule ^(.+?)/?$ $1.php [L]
RewriteRule ^home index.php [NC,L]
RewriteRule ^promo/offers/([0-9]+)/([^/]+)/?$ off.php?pid=$1&ct=$2 [L]
file path is http://localhost/ct/test/off.php?no=1&no2=abc
i want http://localhost/ct/promo/offers/12/abc
this rule doesn't work properly so please tell me what to do.
error is Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.