GTK client for OpenERP 7 is not available. If you use a GTK client of older version, it may connect to the server but the views will not be available. After starting the server you can use your web browser to acces the openerp, by entering localhost:8069 in the address bar if you are running the server in your local machine. If you are accessing it from a remote machine or server then use server_ip_address:8069 (exapmle 192.168.2.35:8069) and also make sure that the port number is 8069, if not use that port number instead of 8069.