apache - symfony2 .htaccess not working with app.php -

im deploying symfony2 app on production server.

im working on web/.htaccess file , can not "redirect" app.php.

my actual file is:

<ifmodule mod_rewrite.c> options +followsymlinks rewriteengine on  # explicitly disable rewriting front controllers rewriterule ^app_dev.php - [l] rewriterule ^app.php - [l]  rewritecond %{request_filename} !-f  # change below before deploying production #rewriterule ^(.*)$ /app.php [qsa,l] rewriterule ^(.*)$ /app_dev.php [qsa,l] 

if copy file on production server (/web folder) redirects dev version. if change comments of 2 last lines:

rewriterule ^(.*)$ /app.php [qsa,l] #rewriterule ^(.*)$ /app_dev.php [qsa,l] 

i got 500 internal server error.

could me? thanks!

based on: greg solution