Just was given an iBook Dual USB laptop. I updated the system to Tiger and plugged in the Ethernet cable from my cable modem that works perfectly with my iMac, and I get a notice that the Ethernet port is in use and can't be used. The person I got it from used the built in modem for dial-up exclusively so to my knowledge the ethernet port was never used. Even so, I assumed that the complete erasure and install of a more updated system would superseded any silliness like this. I have compared the settings in the Network control panel on the imac and ibook, and the setting is set to automatically use DHCP on both. I really can't understand it. I used to have a similar ibook that I would swap the internet with my imac all the time.

Does someone more knowledgeable than me know if the modem is somehow interfering or if there is some other easy solution?

As you can tell, I am knew here, so thanks in advance!