OS X :: Finder Search Cannot Specify Range Of Creation Dates

Using the Finder in 10.5.8, pressing Cmd-F to get to the Search window. I want to look for jpeg files created during December of 2008. I first specify file type = image, press the + to add another constraint, choose "creation date before" . . . today's date comes up by default, with little up/down arrows at the right to allow changes. Well, the arrows do nothing, and I can't edit the date string directly. The only change I'm able to make is when holding down the Alt key, which allows me to use the little up/down arrows to cycle through the months (but not days or years).