Before launching SMB and nmb daemons, launch testparm. This command will read /etc/smb.conf and print which entries will be taken into account.
Then just type /etc/rc.d/init.d/smb start. The following messages should be printed: Starting SMB services: [OK] Starting NMB services: [OK] To check that the daemon is running, run ps aux | grep smbd or /etc/rc.d/init.d/smb status