Scott's analysis is no doubt correct. But just on the off chance that it is something simpler. I have been having all kinds of wierdnesses on OSX 10.4.11 earlier today. Some web searching indicated that people had similar problems a few years back with OS Xafter doing a security update a few days before a timechange. I tried rebooting in case some parts of my system hadn't got the word about the time change. This fixed some of them. Still tracing down others, but thought since your problems seemed to start at the right time, that you might look into it.
HTH, Paul