Re: importing profile from version 3.0.15 to current version possible?
If you look in your profile folder, do you have any database files with a .sqlite extension? That is the current way that bookmarks and other key data is stored. When this format was first adopted, Firefox automatically migrated the data from the old files into the new files. However, I don't know whether Firefox 14 still does that.
If in doubt, perhaps you could update in three steps: install Firefox 3.5, then 3.6, then 14.0.1.
I'd make a backup of the entire profile folder first.
Then you can get the installers from the FTP server: