Catalyst 3750E's and DHCP Snooping

Question

I am using on our perimeter Catalyst 3750E's and 4500 series switches and I have DHCP Snooping enabled.  Each switch has redundant Layer 3 10Gb uplinks back to our Core/Distribution switches.  We have a central DHCP server and each switch writes its snooping database back to a central TFTP server.
This was working fine until we upgraded our Active Directory domain to a 2008 domain, with our DHCP server now residing on a Windows 2008R2 server.
Since the upgrade all 12 stacks of 3750E's will no longer write of the dhcp snooping database.
show ip dhcp snooping database
Agent URL : tftp://<path>
Write delay Timer : 3600 seconds
Abort Timer : 300 seconds
Agent Running : No
Delay Timer Expiry : 17 (00:00:17)
Abort Timer Expiry : Not Running
Last Succeded Time : None
Last Failed Time : None
Last Failed Reason : No failure recorded.
Total Attempts       :        0   Startup Failures :        0
Successful Transfers :        0   Failed Transfers :        0
Successful Reads     :        0   Failed Reads     :        0
Successful Writes    :        0   Failed Writes    :        0
Media Failures       :        0
All of the 4500's (5 of them) however still work as they did prior to the upgrade.
show ip dhcp snooping database
Agent URL : tftp://<path>
Write delay Timer : 3600 seconds
Abort Timer : 60 seconds
Agent Running : No
Delay Timer Expiry : 2737 (00:45:37)
Abort Timer Expiry : Not Running
Last Succeded Time : 07:18:07 EDT Wed Jun 15 2011
Last Failed Time : None
Last Failed Reason : No failure recorded.
Total Attempts       :       13   Startup Failures :        0
Successful Transfers :       13   Failed Transfers :        0
Successful Reads     :        0   Failed Reads     :        0
Successful Writes    :       13   Failed Writes    :        0
Media Failures       :        0
Is this a software bug and has anybody else seen this after upgrading to a Windows 2008 AD domain?

Answer 1

well i found this 
When DHCP snooping is disabled and DAI is enabled, the switch shuts down all the hosts because all 
ARP entries in the ARP table will be checked against a nonexistent DHCP database. When DHCP 
snooping is disabled or in non-DHCP environments, use ARP ACLs to permit or to deny ARP packets
We dont do arp acl 
Here is a little infor on the setup on 6500 
Switch DHCP snooping is enabled
DHCP snooping is configured on following VLANs: Q,W,E,RT,TY,Y
Insertion of option 82 is enabled
Option 82 on untrusted port is not allowed
Verification of hwaddr field is enabled
Verification of giaddr field is enabled
Interface                    Trusted     Rate limit (pps)
GigabitEthernetX/X          yes         unlimited
Port-channel                     yes         unlimited
port config port-channel 
ip arp inspection trust
 ip dhcp snooping trust
2960 config 
Switch DHCP snooping is enabled
DHCP snooping is configured on following VLANs:Q
Insertion of option 82 is disabled
   circuit-id default format: vlan-mod-port
   remote-id: 1111:1111:1111 (MAC)
Option 82 on untrusted port is not allowed
Verification of hwaddr field is enabled
Verification of giaddr field is enabled
DHCP snooping trust/rate is configured on the following Interfaces:
Interface                  Trusted    Allow option    Rate limit (pps)
Port-channel              yes        yes             unlimited
port config 
interface Port-channel
ip arp inspection trust
ip dhcp snooping trust