Did you mean you enabled port fast on the switch ports ?? if no, you should enable portfast on all access-ports
also check on the switch cam table whether you have the PC mac address registered with the associated port.
Do you have the DHCP server on a different subnet from the host subnet ? If then you ll need a IP helper configured on the router routing between the DHCP subnet and host subnet. Dont know if the other 4006 with which DHCP is working, is on the same subnet as the server.
HTH
Sankar Nair
UC Solutions Architect
Pacific Northwest | CDW
CCIE Collaboration #17135 Emeritus