Dhcp cannot be started

Dhcp cannot be started-Linux Enterprise Application-Linux server application information. For details, refer to the following section. # DHCP Server Configuration file.
# See/usr/share/doc/dhcp */dhcpd. conf. sample
#
Ddns-update-style interim;
Ignore client-updates;

Subnet 192.168.10.0 netmask 255.255.255.0 {

# --- Default gateway
Option routers192.168.10.121;
Option subnet-mask255.255.255.0;

Option nis-domain "its-test.com ";
Option domain-name "its-test.com ";
Option domain-name-servers192.168.10.121;

Option time-offset-18000; # Eastern Standard Time
# Option ntp-servers192.168.1.1;
# Option netbios-name-servers192.168.1.1;
# --- Selects point-to-point node (default is hybrid). Don't change this unless
# -- You understand Netbios very well
# Option netbios-node-type 2;

Range dynamic-bootp 192.168.1.240 192.168.1.250;
Default-lease-time 21600;
Max-lease-time 43200;

# We want the nameserver to appear at a fixed address
Host ns {
Next-server ITS-Linux;
Hardware ethernet 00: 0C: 29: 6A: 08: 39;
Fixed-address 192.168.10.121;
}
}

I installed RHEL5 In the Vm, installed dhcpd, And the configuration file is as above.
The IP address of the dhcp server is the local IP address 192.168.10.121.
I still cannot start the dhcp service. Do I know whether it is a configuration problem or other problems?

Thank you.