Sometimes the user does not have their home server set up.
Click on the button at the bottom right hand corner that might say "Office" or "Network" etc.
Select edit current.
Move to Servers.
Make sure Home/Mail sever is set to something.
It should be set to whatever you have in your name and address book record.
If you cannot find this database, do a File->Open Database and select the first non local server and the enter the path as names.nsf. If you still cannot find your record and home server, then try the server name you just used.
If you are off line, then the list of names will not come up if you do not have a local address book anyway.