If your updated to FF 1.0.1 chances are that the plug-ins are not yet updated to work with the newer FireFox .
Although I find FF to be the best brower so far like with anything else I never trust "auto-updates" always best to download and manually install, for one thing auto updating can become corrupt if your connection fails, if you are downloading and know the file size when finished you can compare the file size of what you downloaded to what it should be and get a pretty good idea if you got the complete download.
Another thing I found with FF is that a fresh install is the way to go, just make certain you back up your profile that contains bookmarks and such so you can import them into your new install
