For starters, the call for Implicit plot should be
<< Graphics `ImplicitPlot`
Note that the "quotes" are angled differently (you should be using the key right next to 1 on the top of your keyboard; it gives ` instead of '). I would also recommend ending command lines with ; if you don't want them to individually appear once you execute them (i.e. it hides the output).
Also, ImplicitPlot is obsolete in Mathematica 8; the ContourPlot option does what ImplicitPlot used to do. Here's what I get now: