Please see:

• Back up and restore information in Firefox profiles
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Your profile folder contains all your data (bookmarks, history, downloads data, site and browser preferences, and any other customizations you made) and you can just save its contents to the new profile folder.

However if you do not want to backup your other data, you can just copy two files to the new profile in addition to the bookmarks backup you have:

1. Bookmarks and Browsing History: The places.sqlite file contains all your Firefox bookmarks and the list of all the websites you’ve visited. For more information see Bookmarks.
2. Download history: The downloads.rdf file contains all your Firefox Downloads history.

Please let us know how that works.

That should be downloads.sqlite for the download history (Firefox 2 used downloads.rdf).

See also:

• http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox