K-Meleon appears to be a browser for Windows based on Firefox. At this time it appears it only works with 32 bit versions of windows so if you have vista setup as a 64 bit OS then it may not work. It has an informative wiki and homepage. See links. Links http://kmeleonbrowser.org/ http://kmeleonbrowser.org/wiki/KMeleonWiki/
On the mac I you need to browse out to /Library/Application Support/Firefox/Profiles. Then open the folder that looks like xxxxxxxx.default.In there there should be a file that is labled persidict.dat. Once you find that you should just be able to open it up with a text editor and remove the incorrectly spelled words.