Looks like it can't load the Mongo Module.
First You have to download the stable dll zip file. PHP-MONGO
Download the Threaded-version of the module. Copy the dll file and paste it in C:\wamp64\bin\php\php5.6.19\ext (if wamp). then go to your php.ini file and paste the following script: extension=php_mongo.dll
in the extensions row.
Note: There shouldn't be a ';' before the extension .
Then restart WAMP. In the wamp-php-extension menu you could find the php_mongo. tick mark it. Restart Wamp.
Start mongo and the try executing the following script.
<?php
if($connection = new mongoClient()){
echo "Connected Successfully";
}
?>`
Note: First start the Mongo server.
For more info: PHP/Mongo Manual
If you have problem in start Mongo then Write the command as follows in your Mongo/bin directory:
mongod --storageEngine=mmapv1 --dbpath [your-path]
your-path= The path you want to save the Databse files. (ex: F:\data\db )
The Mongo sever would be running now. Don't close the cmd.