Query string stopped working

I have a Codeigniter site which was working perfectly fine on centOS server. But from yesterday the site is not able to detect the query string and I'm getting 500 server error. The same code is working fine at localhost but at the CentOS server its giving error.

I'm using clean URL but for Jquery's Autocomplete I need query string to be worked. this is my query http://www.site.tld/Search/autocomplete/?country=Yes&query=agou

here is my .htaccess

RewriteEngine ON
Rewritebase /


RewriteCond $1 !^(index.php|assets|css|cache|images|flash|js|weather_images|user_images|new_images|crons|favicon\.ico|robots\.txt|system)

RewriteRule ^(.*)$ index.php/$1 [L]
RewriteRule ^system/(.*)$ system/$1 [L]

#Rewirte images rules
RewriteRule ^images/(.*)$ assets/image开发者_如何转开发s/$1 [L]
RewriteRule ^css/(.*)$ assets/css/$1 [L]
RewriteRule ^js/(.*)$ assets/js/$1 [L]

RewriteRule ^user_images/(.*)$ assets/user_images/$1 [L]


RewriteRule ^flash/(.*)$ assets/flash/$1 [L]

RewriteRule ^new_images/(.*)$ assets/new_images/$1 [L]

RewriteRule ^weather_images/(.*)$ assets/weather_images/$1 [L]

I'm Using Codeigniter 1.7.1

and in my config

$config['uri_protocol'] = "AUTO";

If the only reason you need query strings to work is to use jQuery's autocomplete function, I believe there is a way to modify that function to use a post instead of a get.

How do I set JQuery Autocomplete to POST instead of GET?

Not sure if that is helpful to you, but thought I would throw it out there. I've been doing that successfully for a few areas in my Codeigniter project.

Have you enabled this in config/config.php ??

$config['enable_query_strings'] = TRUE;