OK, could be a couple of things. One thought is that, because both cards look the same, it allocates the wrong card to the LAN. Try swapping the cables over, then rebooting, as see if it gets past the network prob. Or sinply unhook the RED NIC cable form the cable modem, and see if the LAN card gets activated. It should, and you should be able to ping it from a box on the LAN, even if the RED NIC is inactive.
The other could be a ISP issue, as it might not be getting the IP addy for the RED NIC for the ISP. That will stall network as well.
Oh, and if your cable is Telstra, you'll need to load bpalogin before it'll run properly. The files you need should be on the IPCop site somewhere, along with instructions. Should do the initial network connect, though, it just won't log you in.
I use Bigpond cable, and I couldn't get the latest IPCop version running with bpalogin, but wasn't sure if it was me messing up or the files don't work in the new vesrion. No-one could tell me.

I still use the p[revious IPCop version ATM because of this. Never got around to fixing it. Be interested in how you get on if you have Bigpong.
Best place for advice is
Whirlpool Broadband, and ask in the BPA forum if anyone has IPCop latest version running with bpalogin, if that's your issue.
If you have Optus, lucky you, I don't think it needs special config files.
Enough ramble. Let us know what happens
Cheers
Mick
edit: Ah, I see you found Whirpool already. And you have BPA, I see. They didn't help, though, did they?

Now onto
IPCop forum and see if they can help....