My Switch Content Script II works in IE but not Firefox

[ServiceConcepts]

I use Mozilla Firefox typically, but I also open stuff with IE to double-check how it displays. I know this script works for Firefox because when I'm on the dynamic drive page in Firefox for this script (http://www.dynamicdrive.com/dynamicindex17/switchcontent2.htm), it works great... mine, however, the plus and minus buttons do not do anything when clicked. The expand all and collapse all works. Would anyone be able to look at my code and maybe let me know what I am missing, please? Thank you. You can find the page here:
http://store.serviceconcepts.coop/products/cfl-selector/why-buy-from-service-concepts

[ddadmin]

They seem to be working fine for me in FF3.6 except with the last content, though that's because it contains no content it seems.