It’s not a huge deal. Hey, mistakes happen all the time. I’m just surprised to see it happen in an Adobe product, as polished as they like to be and considering how much one has to pay to use the damn things!
I was in the preferences window for Fireworks CS4 (Mac, and at work), just looking around, when I moused over a check box and there it was. I did a double take. I moused over a couple more times to be sure it wasn’t me. Nope, not me. There is, indeed, a typo in Fireworks CS4! Ha! I love it.
Did a quick Google search and it looks like I might even be the first to notice. Although, given the number of Geeks in the world, I’d be surprised if I really am the first. Either way, it’s kind of like an Easter Egg for me. 
Take care!