I couldn't get that little exploit to work on IE 6.1. I guess either they finally fixed it, or it's just not working for me.
IE uses plugins just like any other browser, although IE comes w/ M$ own Java, etc. (inferior proprietary nonsense).
The only plugins that you really need to download for Mozilla is Flash and Java, after that it should run fine for you. I suggest you update to the latest stable though (1.3.1). One of these days Mozilla will come w/ the plugins built in, but it would be a larger download.