Cannot Open Sophos Enterprise Console after upgrad from version 4.0 to 5.1

I successfully upgraded my Sophos Enterprise Console to 5.1

Now I can’’’’t open Enterprise Console.

and give me thie error message :

Managment server connection fieled

This may be due to one of the following :

*  Local network problems

*  managment service has stopped on the server

*  your database service has stopped

*  A firwall is blocking the connection

* The managment service is not installed on the server