How to connect NAV2009 Client to NAV2009 Server?

Hello,

I made a windows Server and a Client. I connected the Client to the server and this works, because I can successfully ping to the Server. Now my problem is that everytime that I run MS Navision 2009 on the client it says it's not connected, and when I press 'No' I have to insert the server address.
When I insert "localhost:7046/DynamicsNAV" it says
'A server was not found at "net.tcp://localhost:7046/DynamicsNAV/Service". Either the URL is incorrect or the server is currently not available.'

Now what could cause this error and how can I fix it?

Thanks in advance!

~Jano