Answer:

The number following the message indicates a database problem. The error number is generated by joomla! and error numbers 1, 2 and 3 indicate the following:

 Error 1 = FATAL ERROR: MySQL support not available. 
 Error 2 = FATAL ERROR: Connection to database server failed.
 Error 3 = FATAL ERROR: Database not found
 

this reflects:

error 1
Joomla! attempts handshake with mysql on the server and fails to even talk to it - this might be because the server does not have mysql installed at all or maybe it is not configured correctly

error 2
The SQL is installed but somethiing causes the failure to login to mysql (this is where it tries the host, username, password data) - may indicate that these details are wrong in your configuration.php

error 3
The handshake has passed station passed 1 and 2 so you can connect to mysql but not select the specific database

So when this happens you have to check all your settings till you have corrected those.