The MySQL server is not running or the location of the MySQL socket is not found.  According to the MySQL manual regarding to this error:

The error (2002) Can't connect to ... normally means that there is no MySQL server running on the system or that you are using an incorrect Unix socket file name or TCP/IP port number when trying to connect to the server. You should also check that the TCP/IP port you are using has not been blocked by a firewall or port blocking service.

If the MySQL information needs to be updated for your PHP Live! system, the following documentation details the procedures.

For more information about this error and possible solutions, visit the MySQL manual.