I'm not sure what happened. I've been using (and LOVING) Firefox Portable for several versions and upgrading without a problem, but this time the update seems not to recognize my previous settings. They're still there in :\PortableApps\FirefoxPortable\Data\profile, but they're not being used -- I'm just getting the default look.
You're using the launcher, right (you would never have seen a problem before if you had been using the same machine)? Also, is Firefox updated?
Vintage!
I'm using the launcher, and the problem started when I upgraded from 2.05 to 2.06. Sorry, I should have said so in my original post.
BTW, I have searched the docs, FAQ, and forums. From what I can tell, this might be a corrupted file or problem with my drive. However, my drive seems to work properly in all other respects, and since reading about the possibility of corrupting the files by removing the drive before properly exiting, I've been especially vigilant.
Probably a corrupted file or two. It happens. You'll see many comments around the board urging people to back up their profiles. There are a number of reasons a file could be written incorrectly, some of which are in no way the flash drive owner's fault (e.g. underpowered USB ports).
Vintage!