RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond $1 !^(index\.php|robots\.txt)
RewriteRule .*$ index.php?/$1 [L]

this is sending my server into an infinite loop according to the error log. max internal redirects and then it kicks out 500 error. i did not write this, it came as part of a script and i'm not sure exactly how to fix it. any ideas?