Pop up dictionary not working (pt. 2?)

I'm using an iBook with a recent clean install of OS X, updated to 10.4.5. However, for a while now (since before I updated to 10.4.5) the popup dictionary has not been working when I press cmd-cntrl-d. I've searched the forums and found this thread. But my problem is obviously not the same because for that guy it ended that his Dictionary.app was not in the Applications folder. Mine is.

I've double-checked the shortcut--it is set to cmd-cntrl-d. And I've made sure that the dictionary is set to "open as panel". I'm trying this is Cocoa apps. I've also checked that the PopupDictDaemon is running. Seriously, this is really annoying me. Does anyone have any recommendations?