Re-configuring Piwik -- Now on new hosting

We have switched to a new hosting service. Piwik was working fine until we switched to the new hosting. Can someone guide me what changes do I have to make with the new hosting to get Piwik work again like before.

When I go to my Piwik login page i.e it shows the below message:

[b]"Your Piwik configuration file appears to be misconfigured. You can either remove config/config.ini.php and resume installation, or correct the database connection settings.

The PDO extension is required for this adapter but the extension is not loaded"[/b]

You must install the PDO php extension