I need help here. My house came pre-wired with ethernet connections in all rooms that converge in a box. I connected the "DM" cable to my Cable Modem and then I connected my cable modem to a TrendNET switch's first port. I have a TrendNET wireless router connected in a room's wall jack which is connected to the second port of the switch. That works perfectly. Anything else I try to connect to the other ports on the switch will show the error on the Subject line above. How can I fix this issue and get internet in all ports? Thank you for your help.