Before I give you further advice, can you describe your landscape and your requirements? Are you using NWDI or are you using NWDS only for local development? First and most important URL to figure out is the SLD URL, you will have to maintain in NWDS. You could use the working NWDS to find it out or just ask basis or other developers. Make sure you can access the SLD from your PC with a browser. See the attached link on how to configure the SLD URL in NWDS.
http://help.sap.com/saphelp_nw73ehp1/helpdata/en/49/09d759e4cf3697e10000000a42189b/frameset.htm