EarthLink disconnect causes kernel panic on dual G4's

Carl Jonard writes: "I have a dual processor 450MHz G4, and I'm using a dialup connection to EarthLink. When I try to disconnect, the Internet Connect application hangs, and attempts to log out or shut down afterwards, almost always causing a kernel panic, which refers to problems with the serial port. This symptom appears to be common with all dual-processor G4 setups. See this MacFixIt Forums thread and this Apple Discussions Board thread, for examples. (Thanks also to Hiram Wilson.)