I installed ZM to FC3 for the first time and thought FC3 was causing a problem that made it so ZM could not connect to a socket.
The socket is the file /tmp/zmdc.sock
With no connection to the socket, ZM could not startup.
Since ZM did not startup, shared memory failed to initialize.
So what was the problem???
the owner of the /tmp/zmdc.sock file was root.
I deleted the /tmp/zmdc.sock file.
Then I was able to startup ZM. ZM created a new /tmp/zmdc.sock file as user apache. Now, finally, everything works.