Turn on SEO URLS Cart Stops Working

Hi,

I am running Opencart 1.5.1.3
The cart works no problem when I do not have SEO url's turned on.
As soon as I turn this on - you can no longer add products to the cart. You press add cart, and nothing happens.

I have used the default .htaccess file that comes with open cart, and I have used the following .hattacess file.

I don't know what else to do - has anyone had this kind of issue.


Options +FollowSymlinks

# Prevent Directoy listing
Options -Indexes

# Prevent Direct Access to files
<FilesMatch "\.(tpl|ini|log)">
Order deny,allow
Deny from all
</FilesMatch>

# SEO URL Settings
#RewriteEngine On
# If your opencart installation does not run on the main web folder make sure you folder it does run in ie. / becomes /shop/

#RewriteBase /
#RewriteCond %{REQUEST_FILENAME} !-f
#RewriteCond %{REQUEST_FILENAME} !-d
#RewriteRule ^([^?]*) index.php?_route_=$1 [L,QSA]


RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)\?*$ index.php?_route_=$1 [L,QSA]

### Additional Settings that may need to be enabled for some servers
### Uncomment the commands by removing the # sign in front of it.
### If you get an "Internal Server Error 500" after enabling any of the following settings, restore the # as this means your host doesn't allow that.

#php_flag register_globals off

#php_flag magic_quotes_gpc Off

#php_value upload_max_filesize 999M

#php_value post_max_size 999M

#php_value max_execution_time 200

#php_value max_input_time 200