Its usual to get this type of error when accessing MySQL from Multiple hosts.
Host ‘host_name’ is blocked because of many connection errors.
Unblock with ‘mysqladmin flush-hosts’
Here the detail explanation from http://dev.mysql.com/doc/refman/5.0/en/blocked-host.html
The value of the max_connect_errors system variable determines how many successive interrupted connection requests are permitted. (See Section 5.1.4, “Server System Variables”.) After max_connect_errors failed requests without a successful connection, mysqld assumes that something is wrong (for example, that someone is trying to break in), and blocks the host from further connections until you issue a FLUSH HOSTS statement or execute a mysqladmin flush-hosts command.