Brwsr/DHCP errore in NT WS w cable modem

System running Win NT WS 4.0 with SP6a connected to cable modem continually get a “DHCP failed to renew a lease for the card…The semaphore timeout period has expired” error when I boot up the system. This causes a “The browser has forced an election on network \Device\NetBT_SMCPWR1 because a master browser was stopped.” error. Ethernet card is SMC Etherpower.