Nav clients can't connect to server

Hello :

Yesterday, we uninstalled the antivirus from the NAV server (Navision 2009) and since then the Navision clients can not connect to the server. The network is working fine, I can ping to the server from the clients. I checked and all the services seem to started fine:

Database Server for Microsoft Dynamics NAV Classic service is running as well as all the network services.

Am I missing somethig? some service that is not running?

I can access the database from the server.

This is the error I get on the client side:


Please help !!!!!