Cannot Access Database Remotely.

I have been using 4d server 2004 within my company quite successfully.  I would however like to be able to access the 4D Server database remotely when I am away from the office and thought that this would be a simple matter of Starting Web Server and Selecting Publish Database at Startup in the Preferences.  However, when I try to log in from a client via a WiFi network I am getting "Error #-10002       The database cannot be used "  error.  The server is connected to the internet via a dynamic IP address - does this matter?  I looked up the IP address on the server and input it into the Custom Screen of the 4d Client still to no avail.   Locally, I have no problem logging in when I am plugged into the local ethernet cable that the server is on.  Can anyone suggest what I may be doing wrong?  Thank you in advance.