Running the 12.2 (55) K-9 code.
Exactly what IOS version? It should be 12.2(55)SEn where "n" is either a blank or a number.
Can you post the configuration example of the port?
Is the switch stack acting as a DHCP server or is there a DHCP server? If there is a DHCP server, is this server connected to the same switch stack?