A whole number of users are experiencing problems with Firefox 3.5 and greater.
The Bookmarks normally stored in the Fast Dial Root Folder (Fast Dial) end up in a Folder called Unsorted Bookmarks.

One way of resolving this is to restore an earlier Version of bookmarks before this happened.

To do this:

Go to Bookmarks/Organise Bookmarks/Import and Backup and click on Restore

Please be careful to restore an earlier backup of your bookmarks. Your latest automatic restore may be corrupt.

In this way you will be able to restore a previously automatically backed up Version of your Bookmarks to Firefox.

As Fast Dial uses places.sqlite (bookmarks) to store it's information, restoring Bookmarks should also restore your Fast Dial.

Please restart Firefox after the restore.

Many thanks