I am facing the same problem.
My laptop is Toshiba A100.
It got buildin Ethernet Intel Pro100 and wifi Intel 3945abg
I tried install ipc OSX 10.5.6
the problem is the system mismatch the wifi and the ethernet.
In Mac, the ethernet can read the Intel 3845abg MAC address.
I really don't know how to fix it.
Most of the answer I found are very old, talking about 10.4.X
I don't think those are helpful.:'(:'(