Not sure what could be causing the problem but one thing that will help those with more of a clue than me would be what version of the server code you are running. You can obtain this by looking at the first line of display in your windows for zone.exe instances and world.exe.
Also, in your zone.exe window for the zone in question, are there any errors returned or does the command return an error when you run it within the game?
Just some additional thoughts that might help people help ya..
