Host name for Windows 7 not found, but local IP address works

I apologize if this question ends up not being specific to Synergy, but I've been having problems getting the right names for my computers.

I'm using a Windows 7 computer for the server, named "WIN", and a Mac running OS X Lion for the client, named "mac", and both are running Synergy 1.4.4. I eventually got everything working by using the name "mac.local" on my server configuration, and my local IP address (192.168.X.X, from ipconfig) for the client.

However, when I try to run the client using "synergyc -f WIN", I get the error message:

failed to connect to server: address not found for: WIN

I'm assuming using the Windows computer's name is a more permanent way to connect to it, so I'd prefer that over the IP address, but I have no idea why it can't find the computer by hostname. When I go to Control Panel and go to System, I see this:

Computer Name:         WIN
Full computer name:    WIN
Computer description:  WIN
Workgroup:             WORKGROUP

So it seems like my computer's named correctly. Also, when I go into Advanced sharing settings, all of my network discovery and sharing settings are turned on.

Is there any other way I can debug this issue to find out why my hostname isn't being found? Thanks in advance!