Did you just install a mod that has a popup when you hover over a forum title? It appears your issue is with another mod, and I have a feeling its the one with the hover over forum title. Its loading an older version of jQuery (v1.4.4) for each and every forum. The error in Firebug is that the function s3Slider is undefined, but I can see the code there, so there is something else conflicting with it.