The error you are getting is from your MySQL server letting you know that a file system connection cannot be established to the db though the socket. The socket is usually used when the connection type relies on the file system and you have the host specified just as localhost.
In the past I have been able to get past issues like this by forcing the connection to go through the web port rather than the socket file by using the ip address of 127.0.0.1. This should be the loopback address that points to localhost on the server.