Failing that, try:
1. GetMyAddress - a useful (free?) utility created by AGGroup.
2. If running Open Transport: open either the AppleTalk or TCP/IP control panels, and do Get Info.
If running classic networking: open the MacTCP control panel, and option-click on Ethernet.
I don't know of a way of finding the hardware address from the classic Network control panel. I assume, btw, that by "hardware address" you mean "48-bit Ethernet MAC address", else the above is a bit useless.