So finally I've managed to get built-in Joomla updating to work by unblocking the whitelist server to server on AlterVista...

Sadly some of the plugins I need to update (because the developer issues a main package then needs the user to update within Joomla to get the latest framework) won't work.

I am receiving this error:

The fact that an exact mirror of my page on WAMP localhost does not give this error leads me to believe that there is something wrong on the side of server configuration that is preventing my Joomla installation from getting these updates to work.

Let me know how to fix this or when you guys fix it on your side.