Each zone.exe running requires a port (typically starting at 7000, and incrementing) - if people are being kicked off your server, it could be that your firewall isn't configured to allow people to connect via those ports, so check that.
It could also be that you don't have enough bandwidth to host it 15 concurrent sessions, but that should result in significant network lag before just disconnecting people. I believe that I read somewhere that the average eq client takes about 5k so you'd need 75k of available upload bandwidth in order to run that many connections.
If you are just dead-set on launching static zones, just drop to a command prompt, go to your eqemu directory and type "start zone.exe <zoneshortname>" for each zone you want to launch statically. Example:
Start->Run->cmd.exe
(assuming that c:\eqemu is your eqemu directory)
Start an instance of the world server (only do this once), and wait for it to finish loading before you start launching zones.
Start a static instance of North Freeport
Code:
start zone.exe freportn
Start a static instance of East Freeport
Code:
start zone.exe freporte
Start a static instance of West Freeport
Code:
start zone.exe freportw
Start a static instance of East Commonlands
Code:
start zone.exe ecommons
You can also write a script to do all of this, if you choose to run static zones on your server. I hope this helps.
Dax