DHCP KEEPS Dropping OUT

Ok Finally

I have been successful in setting up my DHCP on eth0. Thanks for all the help just one thing though
I have assigned a static ip address for eth0
my /etc/sysconfig/network-scripts/ifcfg-eth0 looks like this
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
MACADDR="xx:xx:xx:xx:Xx:xx"
DHCP_HOSTNAME="example"
IPADDR=192.168.1.221
BCAST=192.168.1.255
NETMASK=255.255.255.0

my etc/dhcpd.conf
ddns-update-style interim;
default-lease-time 86400;
max-lease-time 86400;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.1.255;
option routers 192.168.1.254;
option domain-name-servers 192.168.1.1;
option domain-name"ex";
authoritive;

subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.200 192.168.1.222;
range 192.168.1.150 192.168.1.190;
option netbios-name-servers 192.168.1.1;
}

after updating the eth0 I do ifdown eth0 and then ifup eth0
it retains the static ip address for a while and the DHCP works fine after dhcpd
but after about a minute the ip address reverts back to 169.254.206.113 Bcast .255.255 mask etc etc.

and my DHCP server fails. Can anyone explain why this is happening PLEASE