undefined symbol: php_json_encode in Unknown on line 0

Am fighting to install my application on Amazon EC2.. I installed the mongo and php mongo driver then restarted apache to get the above error message.
The problem is loading precedence. Mongo, which is dependent on json.so, is being loaded ahead of the json.so hence crying over ‘Where Is My JSON.so ehiehiehi’
The fix would be to make sure we are loading json first before the mongo – actually this would be hte problem on while loading memcache as well..
On php.ini –
Right above the extension=mongo.so, add extension=json.so
Usually json.so will be loaded through its own ini file json.ini
On Redhat Linux it would be inside

/etc/php.d/

So, go to the json.ini and comment the extension=json.so line
restart httpd/apache and
DOne!