[CentOS] CentOS 4.6 - dhcp issue

Hi - On my CentOS 4 cobbler server i am having some odd dhcp issues.

There is only 1 dhcp server on the network and the cobbler box manages 
the dhcp. When i kick off the PXE install during the PXE phase things 
seem OK then when anaconda tried to get an IP sometimes things work out 
fine and other times it sits waiting for hostname/domainname. From the 
logs you can see that the mac requesting the IP is constant but the IP 
being offered is sometimes 'wrong'. In the 2 examples below nothing is 
changed the differing result is just achieved by trying another install, 
as i said its rather random.

Any thoughts?

thanks


** section of log i see when i have install issue **

Apr 16 14:25:53 cobbler dhcpd: DHCPDISCOVER from 00:0c:29:16:f8:b5 via eth0
Apr 16 14:25:53 cobbler dhcpd: DHCPOFFER on 192.168.12.190 to 
00:0c:29:16:f8:b5 via eth0
Apr 16 14:25:53 cobbler dhcpd: DHCPDISCOVER from 00:0c:29:16:f8:b5 via eth0
Apr 16 14:25:53 cobbler dhcpd: DHCPOFFER on 192.168.12.190 to 
00:0c:29:16:f8:b5 via eth0
Apr 16 14:25:53 cobbler dhcpd: DHCPREQUEST for 192.168.12.212 
(192.168.12.117) from 00:0c:29:16:f8:b5 via eth0: lease 192.168.12.212 
unavailable.
Apr 16 14:25:53 cobbler dhcpd: DHCPNAK on 192.168.12.212 to 
00:0c:29:16:f8:b5 via eth0

** section of log when everything works OK **

Apr 16 14:31:42 cobbler dhcpd: DHCPDISCOVER from 00:0c:29:16:f8:b5 via eth0
Apr 16 14:31:42 cobbler dhcpd: DHCPOFFER on 192.168.12.190 to 
00:0c:29:16:f8:b5 via eth0
Apr 16 14:31:44 cobbler dhcpd: DHCPREQUEST for 192.168.12.190 
(192.168.12.161) from 00:0c:29:16:f8:b5 via eth0
Apr 16 14:31:44 cobbler dhcpd: DHCPACK on 192.168.12.190 to 
00:0c:29:16:f8:b5 via eth0
Apr 16 13:31:44 cobbler in.tftpd[4334]: tftp: client does not accept 
options
Apr 16 14:32:08 cobbler dhcpd: DHCPDISCOVER from 00:0c:29:16:f8:b5 via eth0
Apr 16 14:32:08 cobbler dhcpd: DHCPOFFER on 192.168.12.190 to 
00:0c:29:16:f8:b5 via eth0
Apr 16 14:32:08 cobbler dhcpd: DHCPDISCOVER from 00:0c:29:16:f8:b5 via eth0
Apr 16 14:32:08 cobbler dhcpd: DHCPOFFER on 192.168.12.190 to 
00:0c:29:16:f8:b5 via eth0
Apr 16 14:32:08 cobbler dhcpd: DHCPREQUEST for 192.168.12.190 
(192.168.12.161) from 00:0c:29:16:f8:b5 via eth0
Apr 16 14:32:08 cobbler dhcpd: DHCPACK on 192.168.12.190 to 
00:0c:29:16:f8:b5 via eth0