I never heard of Fireworks CS3 portable, released by Adobe. Fireworks is always installed, it can't be portable (this is not Filezilla, for example, which is very light program and can be portable).
Chances are that you run a version, created by a third party -- I've heard of Photoshop portable, so Fireworks might exist, too, but this is not an oficial version, rather a "hacked" version so that it can work from a USB stick, or any location and be "moved around".
Sorry, I think that I cannot help you with that... I'd suggest installing an official Fireworks version, made by Adobe