DHCP gone ballistic

my DHCP Server is deteriorating rapidly, Scenario:NT 4.0 SP6a
DHCP Scope: 10.10.1-179, 24 bit subnet.
With greater frequency, clients are being served 8 bit subnet masks. Bad_Addresses coming and going within scope. DHCPLOC tool on resource kit reveals no other DHCP server, however is OFFERing addresses but on some OFFERs an ACK is never received from any node. The address being offered shows up in DHCP Admin with no client name associated with the address. After some time must be the server stops the OFFER. Tried deleting the scope and recreating it to no avail. Any HELP would be greatly appreciated